The --help of mp3binder for --tapply contains: Takes the format: 'key1="value",key2="value"'.
However, this "" quotation has a bug because of wrong parsing the , split:

The example... mp3binder.exe . --tapply TIT2="Testing,Bug"
... results in "! Warning: the tag 'Bug' is not a well-known tag, but will be written"

Single '' quotation works: mp3binder.exe . --tapply TIT2='Testing,Bug'

This is a workaround, or maybe meant to work this way anyway(?) - unfortunately there's no way to include rather common ' and/or - chars in the tag, or I dunno how to replace/escape them.

The example... mp3binder.exe . --tapply TIT2='Testing,'Workaround'Bug'
... results in the tag just being Testing,WorkaroundBug

Using Windows release 5.1.0.

Edit: A solution would be to be able to priovide a sidecar file for tagging, with a single TAGTYPE=... in each lin so there is no need for command line parsing - like028bb72