Is there an MSDN / TechNet or other reference for FQL (FAST Query Language) that shows the querytext qualifiers such as filename? For any SharePoint version (2010/2013/2016).
For example, this query works: http://localhost/_api/search/query?querytext='filename:christmas.docx'
and returns documents with that file name (or fragment, I haven't tested that).
I can't find any mention of the "filename" qualifier in the official FQL references such as FAST Query Language (FQL) syntax reference, or the various blogs and articles that I reviewed, except a few Stack questions.