extended view does not show all tags

Support
1

I have scanned my mp3s for idv2 tags with perls mp3::tag module and I found a couple of tags which are not shown in mp3tag (even not with ALT+T) and thus cannot be edited.
Is that a known problem or bug?

Below is an example where I highligted a found item in red.

Tag list shown with ALT+T:
ALBUM ...
ARTIST ...
8AND ...
COMPOSER ...
DATE ...
GENRE Chlout
LANGUAGE ...
TITLE ...
TRACK ...
YEAR ...

IDV2 tags found with perl:

Attached picture : (APIC)

                    Picture Type- Other
                           _Data- binary
                       MIME type- image/jpeg
                     Description-
                        encoding- 0

Private frame : (PRIV)

                           _Data- binary
                            Text- <!--coloro:#FF0000--><span style="color:#FF0000"><!--/coloro--><b>http://www.cdtag.com</b><!--colorc--></span><!--/colorc-->

Album/Movie/Show title : ...
Content type : ...
Date : ...
Title/songname/content description : ...
Language(s) : ...
Lead performer(s)/Soloist(s) : ...
Track number/Position in set : ...

2

Search for PRIV on the forum
e. g.
How to manage Private Tags?
Data Provider Field

DD.20090701.1927.CEST

3

Thanks for the quick reply.
I did not know about the specific PRIV problems.
There are other tags though which are not PRIV and which are also not shown by mp3 tag.
I searched for discussions about hidden tags but could not find anything appropriate.
I also tried the hint which I found at https://docs.mp3tag.de/actions/remove-fields-except but it did not remove the undesired tags either.

Pls. see the highlights in the samples below:

__./test1.mp3
Album/Movie/Show title : ...
Content type : ...
File type : ...
Title/songname/content description : ...
Length : 218000
Lead performer(s)/Soloist(s) : ...
Part of a set : ...
Track number/Position in set : 01
Size : 53...
Year : ...
Terms of use : (USER)

                        Language- <b><!--coloro:#FF0000--><span style="color:#FF0000"><!--/coloro-->Cop
                            Text- yright notice. These materials are protected by United States copyright law and by international treaties. You may use these materials for your personal, non-commercial use only.<!--colorc--></span><!--/colorc--></b>
                        encoding- 0

__./test2.mp3
Attached picture : (APIC)

                    Picture Type- Cover (front)
                           _Data- binary
                       MIME type- image/jpeg
                     Description- 
                        encoding- 0

Comments : (COMM)

                        Language- eng
                     Description- 
                            Text- 
                        encoding- 1

Linked information : (LINK)

                             URL- <b><!--coloro:#FF0000--><span style="color:#FF0000"><!--/coloro-->ttp://www.emusic.com/albums/13101/<!--colorc--></span><!--/colorc--></b>
                              ID- <b><!--coloro:#FF0000--><span style="color:#FF0000"><!--/coloro-->WCOh<!--colorc--></span><!--/colorc--></b>
                            Text- LINK
4

Sorry, I really don't know what these fields are. If they do not show up at the extended tag dialog, they are not supported by Mp3tag.

5

An app that can show all (I hope...) existing tags with their declared ID3v2 frames' names (+ other usefull info about the file) is Medieval Cue Splitter. Freeware, many languages; quick installation, no needs restart Windows. Choose Tools > Audio file information. BTW it's really good app for splitting.

EDIT LATER
Now it handles FLAC, too.