[Feature Request] Display tag information without writing it

Just an idea to be able to display retrieved tag information without ultimately writing it to any files.

For example, we could use any output buffer name prefixed with _mp3tag, e.g. set _mp3tag_sometag, and have its values display in the "Adjust tag information" window, and upon OK, Mp3tag would automatically omit such prefixed output buffers from being written. These temporary buffers would function the same as any other buffer in a script, but simply be disregarded before writing.

A use case:

I want to write a bunch of returned ISRC values, one per track, but the list of ISRC values alone provide no context regarding the listed files on the right (without referring to the source website for example). If one could have a _mp3tag_track and _mp3tag_title output buffer listed along side the ISRCs, it'd provide context and sortability, thus reducing errors writing the tags on the left to the wrong files on the right (which is possible to mess up even with context at times, for example, when attempting to tag a wrong number of tracks). Seeing the track titles/numbers would help when writing a single type of field, such as only genres, or only some UUIDs. Hopefully the UI could also help indicate that a given column won't be written (dimmed/italic values, something visually differentiating).