Yes, I've modified some of the mappings for Matroska video MKV with Mp3tag v3.29. This was motivated by various reports regarding compatibility with Windows Explorer, where some fields were not displayed for MKV files. Here are the details:
I have to think about on how to proceed further. One easy way I can think of is to revert the change regarding TITLE and have it mapped to T=30 TITLE in Matroska. ALBUM would be T=50 TITLE in Matroska.
But this would revert parts of the consolidation process we went through over the past month. Also, there would be new inconsistencies regarding artist and subtitle target types.
What do you think? /cc @RobertM