Muisc app keeps creating Music Library.musiclibrary file in my Users folder.

Here's what I did: I have a iTunes libary on a external harddrive connected to my MacMini running Catalina 10.15.6. I opened the Music App holding the Option key and pointed to the iTunes Library.itl on my external harddrive. The Music app asked me where to create the Music Library.musiclibrary file. I pointed to the external harddrive where my iTunes library is stored. The Music app openend and works fine. So I thought the conversion from iTunes to the Music app was finalized. Then I closed the Music app and after a while re-opened it by clicking on the Dock icon. I noticed a Music Library.musiclibrary file was created in on the MacMini harddrive in the Users/Username/Music/ folder. I deleted the Music Library.musiclibrary file on my external harddrive and moved the Music Library.musiclibrary file from the Users folder to my external harddrive. I then double clicked the Music Library.musiclibrary file on my external harddrive and the Music app opened and worked fine. But yet again a Music Library.musiclibrary file was created in the Users/Username/Music folder on my MacMini harddrive.

My questions:

Why is this Music Library.musiclibrary file created on my MacMini harddrive?

I create a back up every week of my iTunes folder on the external harddrive. When I have to restore the folder do I need to restore the Music Library.musiclibrary file on my MacMini harddrive as well so thta when my external harddrive crashes and my internal harddrive crashes I will be able to restore my Music app content as it was previously?

Thank you very much.

Don