This is a simple glimpse-based query interface for Kym's UFO web pages.
A query can consist of one or more keywords in glimpse format (e.g. "foo;bar" finds all articles with both "foo" and "bar" in the same line) and it will return a list of every line in every relevant accessible file that matches the query. If you click on the line number in the query results, your browser will jump to the corresponding line in the file.
More information is available in the help file (you might want to jump straight to the section on patterns).
NOTE: if you are searching for short keywords then don't enable the spelling error option as it will find very many results. The display will underline only those keywords you actually searched for so may show you many lines that do no appear to match. And the search will be truncated at the max lines and files built into the search that will probably end up showing you nothing much interesting at all.