Welcome to the forum.

The catalog number is prefixed with the Label as there may be more than one catalog number imported and the only method I could think of to differentiate them is to prefix the catalog number with the Label name. If you don't like the Label prefix it is fairly easy to run a post import script which strips the label off for both Discogs and MusicBrainz. The script could be specified in the appropriate Preference section.

If a Discogs catalog number is located I create a User Defined Text Information entry with the description: DISCOGS_CATALOG_NUMBER. Are you sure that Discogs Catalog Number is checked for import in the wizard?

If you are not seeing this created either the data import is not checked, there is no catalog number available or we have a bug. I'm certainly getting the catalog numbers imported in my tests. If you send us the string associated with the created DISCOGS_RELEASE_ID I can test your scenario.

No problem...ask whatever you wish. User Defined Text Info is a label with disclosure on the Audio Tab immediately under the Volume Adjustment field. Click on the disclosure to see and edit the items.

After viewing the information if you still cannot see the DIscogs Catalog number please send me the name of the Album and Artist to search on or if you have the DISCOGS_RELEASE_ID please send me that. I'll look at the raw data.

You're correct. It probably would make more sense on the More Info tab. I would then have enough room to put a table viewer on the tab as I did for User Defined URLS. Editing would still be through the disclosure button. I'll look into this for an upcoming code drop. If not the next, then the one after.