It would be helpful to have a feature in Advanced Search to search on file extension ONLY.  Currently, that search is combined with file name as "Any of these file names or extensions."  Everytime we are looking for a certain extension we have to either (1) manually make sure extra documents did not come through in the search (in the file name itself) or (2) export a metadata report that shows extensions and remove the extras that way.  Both require more time and potential risk of missing something.  Every other platform we have worked in allows for this feature.