this helps with requests that make external HTTP fetches, eg indieweb home pages/posts and federated profiles/posts, which change rarely.
in particular, outbound AP requests that get federated widely (eg Mastodon) result in all of those federated instances making the same bridgy fed requests at the same time, often within just a few seconds. more background: tootsuite/mastodon#4486
for pixelfed, #39. specifically, if the client asks for application/activity+json or application/ld+json (which pixelfed does), fetch and convert to AS2 instead of returning a 302 redirect.
Ryan Barrett