In an effort to promote interest in my format registry browser, I’ve built a Java web application out of it and put it up on Google App Engine at regbrowser.appspot.com. It lets you search PRONOM, UDFR, and the DBPedia structured summaries of format articles, by name, MIME Type, creator, and extension. It uses SPARQL Linked Data queries to obtain data.
It’s still in a rough form; the point is to show what it can do and hopefully get some interest in putting money into further development. Obvious improvements, which I may do shortly, would include checkboxes for which repositories to search and retention of text fields when returning to the search page.
UDFR times out a lot. If you get a timeout error, trying again has a good chance of working.
Mad File Format Science 
I cannot search for application/vnd.oasis.opendocument.presentation:
MIME type field contains disallowed characters.
Sorry, I didn’t include slash (“/”) in the allowed characters. I’ll push a fix within the next 24 hours. Thanks for the bug report!