On the file metadata_db_prefs_backup.json

Os the file "metadata_db_prefs_backup.json".
Is it really needed in the root folder of your library?
I do have some libraries with that file and others without it, i don't know why I can see it is updated sometimes, maybe when I change some preferences.

I've read an old post on library restore saying that:
"If there is no metadata_db_prefs_backup.json file then custom column definitions might be wrong and none of the library-specific preferences will be restored."

And also this note "the file metadata_db_prefs_backup.json contains all the plugboards, custom columns, saved searches, virtual libraries, etc. and is backed up when calibre quits-- basically, anything that IS stored per-library."


So is it required and why isn't it on all libraries I have?
I don't need to have it deleted, just super-curious!

Note: My goal is to share my empty library with all my library-specific preferences (custom columns and so on) so some fellows of mine can start a new empty library with some settings already done.

I was able to create a new empty library from my master library (with feature: Create library / Copy structure) and got an empty master without the file "metadata_db_prefs_backup.json"
I created a copy from that folder and created a library from it and the library settings are there.
It was done in a 32 bit windows machine, didn't test it on a 64 bit machine!