I haven't come across of any project like that, but in case anyone wants to implement this and doesn't know where to start, here's a way to do it on a freedesktop-compatible linux:

Make a userspace daemon process that adds eBPF tracepoints[0] to open{,_at} etc syscalls which match files of your user directories with specific extensions (e.g. .docx).

Associate PIDs that open those files with their .desktop entries[1]

Store results in some database like sqlite3.[2]

Search this database with your favorite interface, like a CLI script or a GNOME shell search provider[3].

I have seen this Rust project on HN which does something similar but with file attribute syscalls, you can use it as reference: https://github.com/javierhonduco/sweeper

[0]: https://github.com/iovisor/bpftrace [1]: https://www.freedesktop.org/wiki/Specifications/desktop-entr... [2]: https://sqlite.org/ [3]: https://developer.gnome.org/documentation/tutorials/search-p...