I tried to find improperly formatted URLs on Wikipedia by entering for a search query with wiki markup, but this doesn't return matches of this markup in Wikipedia. Does Wikipedia have any search options that make it possible to include wiki markup in searches?
The search query that I entered was <ref>http://, and no results showed up for matches of this markup.
Best Answer
Now you can, with regex search:
insource:/\<ref\>http:\/\//(use with care).More information at Help:CirrusSearch.