According to the Metadata Appendix, Publisher is one of the metadata fields for media files, such as MP3s. DEVONthink does not index this field for my MP3s, however:
The field should read “Lyceum Institute”:
I hope this can be fixed 
Where is your data listing coming from?
That’s a Python script I wrote to print the metadata fields of all the mp3s in a directory. If the Publisher metadata field was not empty, it would read Unknown Publisher.
EDIT: Hmm, it doesn’t appear like you can do advanced queries with Publisher… not sure how useful this will be 
And the script is getting the publisher from where?
What do you guys think? Is there something wrong on my end? I hope that this can be fixed and also that Publisher is a filterable option in advanced searches!
Which version of DEVONthink and of macOS do you use? An example file (or link to one) would be useful, thanks.
DEVONthink 3.9.8
macOS 15.3
Here is the mp3 from the OP:
Thank you for the file! Actually only artist, title, album and copyright are currently used in case of audio/video files, the publisher isn’t yet.
Thank you for looking into the issue!