diff --git a/.codecov.yml b/.codecov.yml
new file mode 100644
index 00000000..cc80b2c9
--- /dev/null
+++ b/.codecov.yml
@@ -0,0 +1,10 @@
+# show coverage in CI status, not as a comment. Never consider it a failure.
+comment: off
+coverage:
+  status:
+    project:
+      default:
+        target: 0%
+    patch:
+      default:
+        target: 0%
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 8772e2bb..3b40cd21 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,4 +1,13 @@
-# Local Development
+# Contributing to repo2docker development
+
+This document covers:
+
+- Setting up for Local Development
+- Running Tests
+- Updating and Freezing BuildPack Dependencies
+- Creating a Release
+
+## Setting up for Local Development
 
 To develop & test repo2docker locally, you need:
 
@@ -9,7 +18,7 @@ To develop & test repo2docker locally, you need:
 5. Your favorite text editor
 6. A recent version of [Docker Community Edition](https://www.docker.com/community-edition)
 
-## Clone the repository
+### Clone the repository
 
 First, you need to get a copy of the repo2docker git repository on your local
 disk.
@@ -21,7 +30,7 @@ git clone https://github.com/jupyter/repo2docker
 This will clone repo2docker into a directory called `repo2docker`. You can
 make that your current directory with `cd repo2docker`.
 
-## Set up local virtual environment
+### Set up a local virtual environment
 
 After cloning the repository (or your fork of the repo), you should set up an
 isolated environment to install libraries required for running / developing
@@ -37,7 +46,7 @@ pip3 install -r dev-requirements.txt
 
 This should install all the libraries required for testing & running repo2docker!
 
-## Verify that docker is installed and running
+### Verify that docker is installed and running
 
 If you do not already have [Docker](https://www.docker.com/), you should be able
 to download and install it for your operating system using the links from the
@@ -74,7 +83,9 @@ Then you are good to go!
 ## Running tests
 
 We have a lot of tests for various cases supported by repo2docker in the `tests/`
-subdirectory. These use [py.test](https://docs.pytest.org/).
+subdirectory. If you fix a bug or add new functionality consider adding a new
+test to prevent the bug from coming back. These use
+[py.test](https://docs.pytest.org/).
 
 You can run all the tests with:
 
@@ -88,10 +99,12 @@ If you want to run a specific test, you can do so with:
 py.test -s tests/<path-to-test>
 ```
 
-# Updating libraries installed for all repos
+## Update and Freeze BuildPack Dependencies
 
-For both the `conda` and `virtualenv` (`pip`) base environments, we install specific
-pinned versions of all dependencies. We explicitly list the dependencies
+### Updating libraries installed for all repos
+
+For both the `conda` and `virtualenv` (`pip`) base environments in the **Conda BuildPack** and **Python BuildPack**,
+we install specific pinned versions of all dependencies. We explicitly list the dependencies
 we want, then *freeze* them at commit time to explicitly list all the
 transitive dependencies at current versions. This way, we know that
 all dependencies will have the exact same version installed at all times.
@@ -106,77 +119,93 @@ must follow these steps (with more detailed information in the sections below):
 
 See the subsections below for more detailed instructions.
 
-## Virtualenv dependencies
+### Virtualenv dependencies
 
-There are two files related to virtualenv dependencies:
+1. There are two files related to virtualenv dependencies. Edit as needed.
 
-1. `repo2docker/buildpacks/python/requirements.txt`
+    - `repo2docker/buildpacks/python/requirements.txt`
 
-   Contains list of packages to install in Python3 virtualenvs,
-   which are the default. **This where all Notebook versions &
-   notebook extensions (such as JupyterLab / nteract) go**.
+       Contains list of packages to install in Python3 virtualenvs,
+       which are the default. **This where all Notebook versions &
+       notebook extensions (such as JupyterLab / nteract) go**.
 
-2. `repo2docker/buildpacks/python/requirements2.txt`
+    - `repo2docker/buildpacks/python/requirements2.txt`
 
-   Contains list of packages to install in Python2 virtualenvs, which
-   can be specifically requested by users. **This only needs `IPyKernel`
-   and kernel related libraries** - Notebook / Notebook Extension need
-   not be installed here.
+       Contains list of packages to install in Python2 virtualenvs, which
+       can be specifically requested by users. **This only needs `IPyKernel`
+       and kernel related libraries** Notebook / Notebook Extension need
+       not be installed here.
 
-After you edit either of these files to add a new package / bump version on
-an existing package, run `./repo2docker/buildpacks/python/freeze.bash`.
+2. After you edit either of these files to add a new package / bump version on
+   an existing package, run:
 
-This script will resolve dependencies and write them to the respective `.frozen.txt`
-files. You will need Python3 and Python2 with virtualenv to run the script.
+   ```bash
+   ./repo2docker/buildpacks/python/freeze.bash
+   ```
 
-All the `.txt` files in `repo2docker/buildpacks/python/` should be committed to git.
+   This script will resolve dependencies and write them to the respective `.frozen.txt`
+   files.
 
-## Conda dependencies
+   Note: If you do not have Python3 and Python2 with virtualenv, the script
+   will create and build Docker containers to process the frozen files.
 
-There are two files related to conda dependencies:
+3. All the `.txt` files in `repo2docker/buildpacks/python/` should be committed to git.
 
-1. `repo2docker/buildpacks/conda/environment.yml`
+4. Make a pull request.
 
-   Contains list of packages to install in Python3 conda environments,
-   which are the default. **This is where all Notebook versions &
-   notebook extensions (such as JupyterLab / nteract) go**.
+### Conda dependencies
 
-2. `repo2docker/buildpacks/conda/environment.py-2.7.yml`
+1. There are two files related to conda dependencies. Edit as needed.
 
-   Contains list of packages to install in Python2 conda environments, which
-   can be specifically requested by users. **This only needs `IPyKernel`
-   and kernel related libraries** - Notebook / Notebook Extension need
-   not be installed here.
+    - `repo2docker/buildpacks/conda/environment.yml`
 
-Once you edit either of these files to add a new package / bump version on
-an existing package, you should then run `./repo2docker/buildpacks/conda/freeze.py`.
-This script will resolve dependencies and write them to the respective `.frozen.yml`
-files. You will need `docker` installed to run this script.
+       Contains list of packages to install in Python3 conda environments,
+       which are the default. **This is where all Notebook versions &
+       notebook extensions (such as JupyterLab / nteract) go**.
 
-After the freeze script finishes, a number of files will have been created.
-Commit the following subset of files to git:
+    - `repo2docker/buildpacks/conda/environment.py-2.7.yml`
 
-```
-repo2docker/buildpacks/conda/environment.yml
-repo2docker/buildpacks/conda/environment.frozen.yml
-repo2docker/buildpacks/conda/environment.py-2.7.yml
-repo2docker/buildpacks/conda/environment.py-2.7.frozen.yml
-repo2docker/buildpacks/conda/environment.py-3.5.frozen.yml
-repo2docker/buildpacks/conda/environment.py-3.6.frozen.yml
-```
+       Contains list of packages to install in Python2 conda environments, which
+       can be specifically requested by users. **This only needs `IPyKernel`
+       and kernel related libraries**. Notebook / Notebook Extension need
+       not be installed here.
 
+2. Once you edit either of these files to add a new package / bump version on
+   an existing package, you should then run:
 
-## Make a Pull Request
+   ```bash
+   python ./repo2docker/buildpacks/conda/freeze.py
+   ```
+
+   This script will resolve dependencies and write them to the respective `.frozen.yml`
+   files. You will need `docker` installed to run this script.
+
+3. After the freeze script finishes, a number of files will have been created.
+   Commit the following subset of files to git:
+
+    ```
+    repo2docker/buildpacks/conda/environment.yml
+    repo2docker/buildpacks/conda/environment.frozen.yml
+    repo2docker/buildpacks/conda/environment.py-2.7.yml
+    repo2docker/buildpacks/conda/environment.py-2.7.frozen.yml
+    repo2docker/buildpacks/conda/environment.py-3.5.frozen.yml
+    repo2docker/buildpacks/conda/environment.py-3.6.frozen.yml
+    ```
+
+4. Make a pull request.
+
+### Make a Pull Request
 
 Once you've made the commit, please make a Pull Request to the `jupyter/repo2docker`
 repository, with a description of what versions were bumped / what new packages were
-added and why.
+added and why. If you fix a bug or add new functionality consider adding a new
+test to prevent the bug from coming back/the feature breaking in the future.
 
-# Release Process
+## Creating a Release
 
 We try to make a release of repo2docker every few months if possible.
 
-## Access
+## Obtain access credentials
 
 To release repo2docker, you will need proper access credentials prior to beginning the process.
 
@@ -186,7 +215,7 @@ To release repo2docker, you will need proper access credentials prior to beginni
 
 If you do not have access to any of these, please contact a current maintainer of the project!
 
-## Steps
+## Release Process Steps
 
 1. Make a PR bumping version number of repo2docker in the
    `setup.py` file (like https://github.com/jupyter/repo2docker/pull/221),
diff --git a/README.md b/README.md
index 9a6a900a..88b44174 100644
--- a/README.md
+++ b/README.md
@@ -1,11 +1,10 @@
 # jupyter-repo2docker
 
-
 [![Build Status](https://travis-ci.org/jupyter/repo2docker.svg?branch=master)](https://travis-ci.org/jupyter/repo2docker)
 [![Documentation Status](https://readthedocs.org/projects/repo2docker/badge/?version=latest)](http://repo2docker.readthedocs.io/en/latest/?badge=latest)
 
-**jupyter-repo2docker** takes as input a repository source, such as a GitHub repo. It then builds, runs, and/or pushes Docker images built from
-that source.
+**jupyter-repo2docker** takes as input a repository source, such as a GitHub
+repo. It then builds, runs, and/or pushes Docker images built from that source.
 
 See the [repo2docker documentation](http://repo2docker.readthedocs.io)
 for more information.
@@ -16,15 +15,17 @@ for more information.
    is recommended.
 2. Python 3.4+.
 
+Supported on Linux and macOS. [See documentation note about Windows support.](http://repo2docker.readthedocs.io/en/latest/install.html#note-about-windows-support)
+
 ## Installation
 
-To install from pypi, the python packaging index:
+To install from PyPI, the python packaging index, using `pip`:
 
 ```bash
 pip install jupyter-repo2docker
 ```
 
-To install from source and start contributing:
+To install from source:
 
 ```bash
 git clone https://github.com/jupyter/repo2docker.git
@@ -34,29 +35,29 @@ pip install -e .
 
 ## Usage
 
-The core feature of repo2docker is to fetch a repo (from github or locally), build a container
-image based on the specifications found in the repo & optionally launch a local Jupyter Notebook
-you can use to explore it.
+The core feature of repo2docker is to fetch a repo (from github or locally),
+build a container image based on the specifications found in the repo &
+optionally launch a local Jupyter Notebook you can use to explore it.
 
 **Note that Docker needs to be running on your machine for this to work.**
 
 Example:
 
 ```bash
-jupyter-repo2docker https://github.com/jakevdp/PythonDataScienceHandbook
+jupyter-repo2docker https://github.com/norvig/pytudes
 ```
 
-After building (it might take a while!), it should output in your terminal something like:
+After building (it might take a while!), it should output in your terminal
+something like:
 
-
-```
+```bash
     Copy/paste this URL into your browser when you connect for the first time,
     to login with a token:
         http://0.0.0.0:36511/?token=f94f8fabb92e22f5bfab116c382b4707fc2cade56ad1ace0
 ```
 
-If you copy paste that URL into your browser you will see a Jupyter Notebook with the
-contents of the repository you had just built!
+If you copy paste that URL into your browser you will see a Jupyter Notebook
+with the contents of the repository you had just built!
 
 For more information on how to use ``repo2docker``, see the
 [usage guide](http://repo2docker.readthedocs.io/en/latest/usage.html).
@@ -64,8 +65,8 @@ For more information on how to use ``repo2docker``, see the
 ## Repository specifications
 
 Repo2Docker looks for configuration files in the source repository to
-determine how the Docker image should be built.
-It is philosophically similar to [Heroku Build Packs](https://devcenter.heroku.com/articles/buildpacks).
+determine how the Docker image should be built. It is philosophically similar
+to [Heroku Build Packs](https://devcenter.heroku.com/articles/buildpacks).
 
 For a list of the configuration files that ``repo2docker`` can use,
 see the [usage guide](http://repo2docker.readthedocs.io/en/latest/usage.html).
diff --git a/repo2docker/buildpacks/base.py b/repo2docker/buildpacks/base.py
index 41fea076..1599ff8f 100644
--- a/repo2docker/buildpacks/base.py
+++ b/repo2docker/buildpacks/base.py
@@ -170,7 +170,7 @@ class BuildPack:
             # FIXME: Use npm from nodesource!
             # Everything seems to depend on npm these days, unfortunately.
             "npm",
-            
+
             "unzip",
         }
 
diff --git a/repo2docker/buildpacks/conda/__init__.py b/repo2docker/buildpacks/conda/__init__.py
index ef39e9a0..4de9638e 100644
--- a/repo2docker/buildpacks/conda/__init__.py
+++ b/repo2docker/buildpacks/conda/__init__.py
@@ -1,6 +1,4 @@
-"""
-Buildpack for conda environments
-"""
+"""BuildPack for conda environments"""
 import os
 import re
 
@@ -15,16 +13,48 @@ HERE = os.path.dirname(os.path.abspath(__file__))
 
 
 class CondaBuildPack(BaseImage):
+    """A conda BuildPack.
+
+    Uses miniconda since it is more lightweight than Anaconda.
+
+    """
     def get_env(self):
+        """Return environment variables to be set.
+
+        We set `CONDA_DIR` to the conda install directory and
+        the `NB_PYTHON_PREFIX` to the location of the jupyter binary.
+
+        """
         return super().get_env() + [
             ('CONDA_DIR', '${APP_BASE}/conda'),
             ('NB_PYTHON_PREFIX', '${CONDA_DIR}'),
         ]
 
     def get_path(self):
+        """Return paths (including conda environment path) to be added to
+        the PATH environment variable.
+
+        """
         return super().get_path() + ['${CONDA_DIR}/bin']
 
     def get_build_scripts(self):
+        """
+        Return series of build-steps common to all Python 3 repositories.
+
+        All scripts here should be independent of contents of the repository.
+
+        This sets up through `install-miniconda.bash` (found in this directory):
+
+        - a directory for the conda environment and its ownership by the
+          notebook user
+        - a Python 3 interpreter for the conda environment
+        - a Python 3 jupyter kernel
+        - a frozen base set of requirements, including:
+            - support for Jupyter widgets
+            - support for JupyterLab
+            - support for nteract
+
+        """
         return super().get_build_scripts() + [
             (
                 "root",
@@ -41,6 +71,20 @@ class CondaBuildPack(BaseImage):
     }
 
     def get_build_script_files(self):
+        """
+        Dict of files to be copied to the container image for use in building.
+
+        This is copied before the `build_scripts` & `assemble_scripts` are
+        run, so can be executed from either of them.
+
+        It's a dictionary where the key is the source file path in the host
+        system, and the value is the destination file path inside the
+        container image.
+
+        This currently adds a frozen set of Python requirements to the dict
+        of files.
+
+        """
         files = {
             'conda/install-miniconda.bash': '/tmp/install-miniconda.bash',
         }
@@ -69,10 +113,11 @@ class CondaBuildPack(BaseImage):
 
     @property
     def python_version(self):
-        """
-        Detect the Python version for a given environment.yml
+        """Detect the Python version for a given `environment.yml`
+
+        Will return 'x.y' if version is found (e.g '3.6'),
+        or a Falsy empty string '' if not found.
 
-        Will return 'x.y' if found, or Falsy '' if not.
         """
         environment_yml = self.binder_path('environment.yml')
         if not os.path.exists(environment_yml):
@@ -109,6 +154,8 @@ class CondaBuildPack(BaseImage):
         return self.python_version and self.python_version.split('.')[0] == '2'
 
     def get_assemble_scripts(self):
+        """Return series of build-steps specific to this source repository.
+        """
         assembly_scripts = []
         environment_yml = self.binder_path('environment.yml')
         env_name = 'kernel' if self.py2 else 'root'
@@ -124,4 +171,6 @@ class CondaBuildPack(BaseImage):
         return super().get_assemble_scripts() + assembly_scripts
 
     def detect(self):
+        """Check if current repo should be built with the Conda BuildPack.
+        """
         return os.path.exists(self.binder_path('environment.yml')) and super().detect()
diff --git a/repo2docker/buildpacks/conda/environment.frozen.yml b/repo2docker/buildpacks/conda/environment.frozen.yml
index 458ac45a..b17b9543 100644
--- a/repo2docker/buildpacks/conda/environment.frozen.yml
+++ b/repo2docker/buildpacks/conda/environment.frozen.yml
@@ -1,5 +1,5 @@
 # AUTO GENERATED FROM environment.py-3.6.yml, DO NOT MANUALLY MODIFY
-# Frozen on 2018-03-13 17:43:53 UTC
+# Frozen on 2018-03-20 00:47:27 UTC
 name: r2d
 channels:
   - conda-forge
@@ -30,23 +30,23 @@ dependencies:
   - nbconvert=5.3.1=py_1
   - nbformat=4.4.0=py36_0
   - ncurses=5.9=10
-  - notebook=5.4.0=py36_0
+  - notebook=5.4.1=py36_0
   - openssl=1.0.2n=0
-  - pandoc=2.1.2=0
+  - pandoc=2.1.3=0
   - pandocfilters=1.4.1=py36_0
   - parso=0.1.1=py_0
   - pexpect=4.4.0=py36_0
   - pickleshare=0.7.4=py36_0
-  - pip=9.0.1=py36_1
+  - pip=9.0.2=py36_0
   - prompt_toolkit=1.0.15=py36_0
   - ptyprocess=0.5.2=py36_0
   - pygments=2.2.0=py36_0
   - python=3.6.4=0
-  - python-dateutil=2.6.1=py36_0
+  - python-dateutil=2.7.0=py_0
   - pyzmq=17.0.0=py36_3
   - readline=7.0=0
   - send2trash=1.5.0=py_0
-  - setuptools=38.5.2=py36_0
+  - setuptools=39.0.1=py36_0
   - simplegeneric=0.8.1=py36_0
   - six=1.11.0=py36_1
   - sqlite=3.20.1=2
diff --git a/repo2docker/buildpacks/conda/environment.py-2.7.frozen.yml b/repo2docker/buildpacks/conda/environment.py-2.7.frozen.yml
index 1b3f297e..a98aa621 100644
--- a/repo2docker/buildpacks/conda/environment.py-2.7.frozen.yml
+++ b/repo2docker/buildpacks/conda/environment.py-2.7.frozen.yml
@@ -1,5 +1,5 @@
 # AUTO GENERATED FROM environment.py-2.7.yml, DO NOT MANUALLY MODIFY
-# Frozen on 2018-03-13 17:38:07 UTC
+# Frozen on 2018-03-20 00:42:45 UTC
 name: r2d
 channels:
   - conda-forge
@@ -24,16 +24,16 @@ dependencies:
   - pathlib2=2.3.0=py27_0
   - pexpect=4.4.0=py27_0
   - pickleshare=0.7.4=py27_0
-  - pip=9.0.1=py27_1
+  - pip=9.0.2=py27_0
   - prompt_toolkit=1.0.15=py27_0
   - ptyprocess=0.5.2=py27_0
   - pygments=2.2.0=py27_0
   - python=2.7.14=4
-  - python-dateutil=2.6.1=py27_0
+  - python-dateutil=2.7.0=py_0
   - pyzmq=17.0.0=py27_3
   - readline=7.0=0
   - scandir=1.7=py27_0
-  - setuptools=38.5.2=py27_0
+  - setuptools=39.0.1=py27_0
   - simplegeneric=0.8.1=py27_0
   - singledispatch=3.4.0.3=py27_0
   - six=1.11.0=py27_1
diff --git a/repo2docker/buildpacks/conda/environment.py-3.5.frozen.yml b/repo2docker/buildpacks/conda/environment.py-3.5.frozen.yml
index 66c6383d..3d69e6be 100644
--- a/repo2docker/buildpacks/conda/environment.py-3.5.frozen.yml
+++ b/repo2docker/buildpacks/conda/environment.py-3.5.frozen.yml
@@ -1,5 +1,5 @@
 # AUTO GENERATED FROM environment.py-3.5.yml, DO NOT MANUALLY MODIFY
-# Frozen on 2018-03-13 17:40:14 UTC
+# Frozen on 2018-03-20 00:43:53 UTC
 name: r2d
 channels:
   - conda-forge
@@ -30,23 +30,23 @@ dependencies:
   - nbconvert=5.3.1=py_1
   - nbformat=4.4.0=py35_0
   - ncurses=5.9=10
-  - notebook=5.4.0=py35_0
+  - notebook=5.4.1=py35_0
   - openssl=1.0.2n=0
-  - pandoc=2.1.2=0
+  - pandoc=2.1.3=0
   - pandocfilters=1.4.1=py35_0
   - parso=0.1.1=py_0
   - pexpect=4.4.0=py35_0
   - pickleshare=0.7.4=py35_0
-  - pip=9.0.1=py35_1
+  - pip=9.0.2=py35_0
   - prompt_toolkit=1.0.15=py35_0
   - ptyprocess=0.5.2=py35_0
   - pygments=2.2.0=py35_0
   - python=3.5.5=0
-  - python-dateutil=2.6.1=py35_0
+  - python-dateutil=2.7.0=py_0
   - pyzmq=17.0.0=py35_3
   - readline=7.0=0
   - send2trash=1.5.0=py_0
-  - setuptools=38.5.2=py35_0
+  - setuptools=39.0.1=py35_0
   - simplegeneric=0.8.1=py35_0
   - six=1.11.0=py35_1
   - sqlite=3.20.1=2
diff --git a/repo2docker/buildpacks/conda/environment.py-3.6.frozen.yml b/repo2docker/buildpacks/conda/environment.py-3.6.frozen.yml
index 458ac45a..b17b9543 100644
--- a/repo2docker/buildpacks/conda/environment.py-3.6.frozen.yml
+++ b/repo2docker/buildpacks/conda/environment.py-3.6.frozen.yml
@@ -1,5 +1,5 @@
 # AUTO GENERATED FROM environment.py-3.6.yml, DO NOT MANUALLY MODIFY
-# Frozen on 2018-03-13 17:43:53 UTC
+# Frozen on 2018-03-20 00:47:27 UTC
 name: r2d
 channels:
   - conda-forge
@@ -30,23 +30,23 @@ dependencies:
   - nbconvert=5.3.1=py_1
   - nbformat=4.4.0=py36_0
   - ncurses=5.9=10
-  - notebook=5.4.0=py36_0
+  - notebook=5.4.1=py36_0
   - openssl=1.0.2n=0
-  - pandoc=2.1.2=0
+  - pandoc=2.1.3=0
   - pandocfilters=1.4.1=py36_0
   - parso=0.1.1=py_0
   - pexpect=4.4.0=py36_0
   - pickleshare=0.7.4=py36_0
-  - pip=9.0.1=py36_1
+  - pip=9.0.2=py36_0
   - prompt_toolkit=1.0.15=py36_0
   - ptyprocess=0.5.2=py36_0
   - pygments=2.2.0=py36_0
   - python=3.6.4=0
-  - python-dateutil=2.6.1=py36_0
+  - python-dateutil=2.7.0=py_0
   - pyzmq=17.0.0=py36_3
   - readline=7.0=0
   - send2trash=1.5.0=py_0
-  - setuptools=38.5.2=py36_0
+  - setuptools=39.0.1=py36_0
   - simplegeneric=0.8.1=py36_0
   - six=1.11.0=py36_1
   - sqlite=3.20.1=2
diff --git a/repo2docker/buildpacks/conda/environment.yml b/repo2docker/buildpacks/conda/environment.yml
index 804bcb71..26ef24af 100644
--- a/repo2docker/buildpacks/conda/environment.yml
+++ b/repo2docker/buildpacks/conda/environment.yml
@@ -3,6 +3,6 @@ dependencies:
   - ipywidgets==7.1.1
   - jupyterlab==0.31.5
   - tornado==4.5.3
-  - notebook==5.4.0
+  - notebook==5.4.1
   - pip:
     - nteract_on_jupyter==1.5.0
diff --git a/repo2docker/buildpacks/conda/freeze.py b/repo2docker/buildpacks/conda/freeze.py
index 37790781..dc8980ed 100755
--- a/repo2docker/buildpacks/conda/freeze.py
+++ b/repo2docker/buildpacks/conda/freeze.py
@@ -21,7 +21,7 @@ from ruamel.yaml import YAML
 
 MINICONDA_VERSION = '4.3.27'
 # need conda ≥ 4.4 to avoid bug adding spurious pip dependencies
-CONDA_VERSION = '4.4.8'
+CONDA_VERSION = '4.4.11'
 
 HERE = pathlib.Path(os.path.dirname(os.path.abspath(__file__)))
 
diff --git a/repo2docker/buildpacks/docker.py b/repo2docker/buildpacks/docker.py
index 8baa5dfb..8f3aefa0 100644
--- a/repo2docker/buildpacks/docker.py
+++ b/repo2docker/buildpacks/docker.py
@@ -1,5 +1,4 @@
-"""
-Generates a variety of Dockerfiles based on an input matrix
+"""Generates a variety of Dockerfiles based on an input matrix
 """
 import os
 import docker
@@ -7,17 +6,21 @@ from .base import BuildPack
 
 
 class DockerBuildPack(BuildPack):
+    """Docker BuildPack"""
     dockerfile = "Dockerfile"
 
     def detect(self):
+        """Check if current repo should be built with the Docker BuildPack"""
         return os.path.exists(self.binder_path('Dockerfile'))
 
     def render(self):
+        """Render the Dockerfile using by reading it from the source repo"""
         Dockerfile = self.binder_path('Dockerfile')
         with open(Dockerfile) as f:
             return f.read()
 
     def build(self, image_spec, memory_limit, build_args):
+        """Build a Docker image based on the Dockerfile in the source repo."""
         limits = {
             # Always disable memory swap for building, since mostly
             # nothing good can come of that.
diff --git a/repo2docker/buildpacks/legacy/__init__.py b/repo2docker/buildpacks/legacy/__init__.py
index fe7c56ca..5219b2ae 100644
--- a/repo2docker/buildpacks/legacy/__init__.py
+++ b/repo2docker/buildpacks/legacy/__init__.py
@@ -1,5 +1,10 @@
-"""
-Generates a variety of Dockerfiles based on an input matrix
+"""Generates Dockerfiles from the legacy Binder Dockerfiles
+based on `andrewosh/binder-base`.
+
+The Dockerfile is amended to add the contents of the repository
+to the image and install a supported version of the notebook
+and IPython kernel.
+
 """
 import os
 import shutil
@@ -7,7 +12,7 @@ from textwrap import dedent
 from ..docker import DockerBuildPack
 
 class LegacyBinderDockerBuildPack(DockerBuildPack):
-
+    """Legacy build pack for compatibility to first version of Binder."""
     dockerfile = '._binder.Dockerfile'
 
     legacy_prependix = dedent(r"""
@@ -39,6 +44,13 @@ class LegacyBinderDockerBuildPack(DockerBuildPack):
     """)
 
     def render(self):
+        """Render buildpack into a Dockerfile.
+
+        Render legacy image source (andrewosh/binder-base at a specific commit)
+        and then prependix. Render appendix (post-build commands) at the end of
+        the Dockerfile.
+
+        """
         segments = [
             'FROM andrewosh/binder-base@sha256:eabde24f4c55174832ed8795faa40cea62fc9e2a4a9f1ee1444f8a2e4f9710ee',
             self.legacy_prependix,
@@ -52,12 +64,27 @@ class LegacyBinderDockerBuildPack(DockerBuildPack):
         return '\n'.join(segments)
 
     def get_build_script_files(self):
-       return {
+        """
+        Dict of files to be copied to the container image for use in building.
+
+        This is copied before the `build_scripts` & `assemble_scripts` are
+        run, so can be executed from either of them.
+
+        It's a dictionary where the key is the source file path in the host
+        system, and the value is the destination file path inside the
+        container image.
+
+        This currently adds a frozen set of Python requirements to the dict
+        of files.
+         
+        """
+        return {
             'legacy/root.frozen.yml': '/tmp/root.frozen.yml',
             'legacy/python3.frozen.yml': '/tmp/python3.frozen.yml',
         }
             
     def build(self, image_spec, memory_limit, build_args):
+        """Build a legacy Docker image."""
         with open(self.dockerfile, 'w') as f:
             f.write(self.render())
         for env in ('root', 'python3'):
@@ -70,6 +97,8 @@ class LegacyBinderDockerBuildPack(DockerBuildPack):
         return super().build(image_spec, memory_limit, build_args)
 
     def detect(self):
+        """Check if current repo should be built with the Legacy BuildPack.
+        """
         try:
             with open('Dockerfile', 'r') as f:
                 for line in f:
diff --git a/repo2docker/buildpacks/python/requirements.frozen.txt b/repo2docker/buildpacks/python/requirements.frozen.txt
index 2444c4be..d884a4a5 100644
--- a/repo2docker/buildpacks/python/requirements.frozen.txt
+++ b/repo2docker/buildpacks/python/requirements.frozen.txt
@@ -1,5 +1,5 @@
 # AUTO GENERATED FROM requirements.txt, DO NOT MANUALLY MODIFY
-# Frozen on Thu Mar 15 11:51:16 UTC 2018
+# Frozen on Tue Mar 20 00:18:43 UTC 2018
 bleach==2.1.3
 decorator==4.2.1
 entrypoints==0.2.3
@@ -19,7 +19,7 @@ MarkupSafe==1.0
 mistune==0.8.3
 nbconvert==5.3.1
 nbformat==4.4.0
-notebook==5.4.0
+notebook==5.4.1
 nteract-on-jupyter==1.5.0
 pandocfilters==1.4.2
 parso==0.1.1
diff --git a/repo2docker/buildpacks/python/requirements.txt b/repo2docker/buildpacks/python/requirements.txt
index 2812eb71..811d36e4 100644
--- a/repo2docker/buildpacks/python/requirements.txt
+++ b/repo2docker/buildpacks/python/requirements.txt
@@ -1,4 +1,4 @@
-notebook==5.4.0
+notebook==5.4.1
 tornado==4.5.3
 ipywidgets==7.1.1
 jupyterlab==0.31.5
diff --git a/repo2docker/buildpacks/python/requirements2.frozen.txt b/repo2docker/buildpacks/python/requirements2.frozen.txt
index b2f5435a..8d44e4bd 100644
--- a/repo2docker/buildpacks/python/requirements2.frozen.txt
+++ b/repo2docker/buildpacks/python/requirements2.frozen.txt
@@ -1,5 +1,5 @@
 # AUTO GENERATED FROM requirements2.txt, DO NOT MANUALLY MODIFY
-# Frozen on Thu Mar 15 11:52:00 UTC 2018
+# Frozen on Tue Mar 20 00:20:49 UTC 2018
 backports-abc==0.5
 backports.shutil-get-terminal-size==1.0.0
 certifi==2018.1.18