ONly just this w/e I found a album where tracks have 'Artists' ... this in Musicbrainz.
I however cannot find this anywhere in MP3tag, tried also extend field of course. Does this require development work?
No, you simply create a new field (in the extended tags dialogue) and type in the name of that new field.
Now it should also be available in dropdown lists for field names.
OK, this indeed works, thanks.
So I understand that MP3Tag does not read possible fields from the file then...which I was expecting to show in the list of 'extended'
MP3tag reads the tag fields as you could see in the extended tags dialogue.
But it does not add that to the dropdown list of field names until you have actually done something with that name.
E.g. you could create an action of the type "Format value" for a totally new and hitherto unknown field of the name SUPERCALIFRAGILISTICEXPIALIDOCIOUS by simply typing it in.