Bulk edit favorites folder/file

I have "overloaded" my favorites in LMS, and would like to remove a few dozen entries....the gui works, but 1 at a time is pretty tedious ..

I see 2 favorites.opml files, and tried editing (nano) ... the edits do not stay ---

I am editing the files in the /var/lib/squeezeboxserver/prefs folder (ubuntu 20.04) ... maybe there is another file ??

Any gudance appreciated...