Use the correct content type

mod/oexchange.php

@@ -32,7 +32,7 @@ function oexchange_init(App $a) {
 		$tpl = Renderer::getMarkupTemplate('oexchange_xrd.tpl');
 
 		$o = Renderer::replaceMacros($tpl, ['$base' => DI::baseUrl()]);
-		System::httpExit($o, Response::TYPE_XML);
+		System::httpExit($o, Response::TYPE_XML, 'application/xrd+xml');
 	}
 }
 

src/Module/WellKnown/HostMeta.php

@@ -54,6 +54,6 @@ class HostMeta extends BaseModule
 			'$bigkey' => Salmon::salmonKey($config->get('system', 'site_pubkey'))
 		]);
 
-		System::httpExit($content, Response::TYPE_XML);
+		System::httpExit($content, Response::TYPE_XML, 'application/xrd+xml');
 	}
 }

src/Module/Xrd.php

@@ -262,6 +262,6 @@ class Xrd extends BaseModule
 
 		header('Access-Control-Allow-Origin: *');
 
-		System::httpExit($arr['xml'], Response::TYPE_XML);
+		System::httpExit($arr['xml'], Response::TYPE_XML, 'application/xrd+xml');
 	}
 }