I tried to subscribe to the RSS and ATOM feeds on the Recent Changes page in my (MediaWiki) wiki. Bandit gave the following error:
Refresh feed ‘Wikis\mydomain.net‘ failed with error: The XML declaration is unexpected. Line 2, position 3.
It turns out that there was a blank line at the bottom of my LDAPAuthentication.php script, which was added to the beginning of the feed. This meant that the >?xml version=”1.0″ encoding=”utf-8″?> appeared on line 2, but it must be on line 1 or the XML is invalid. Apparently, blank spaces in LocalSettings.php can have the same effect.
Having fixed it, I now can’t recreate the error. I’m assuming this is because of caching, or because I haven’t changed anything in the wiki since fixing it.