Good question, Anglo

The cards used to create this were in the "shelflist" catalog, meaning their primary reference was the shelflist number, or "AFS number." Since that was the master catalog from which the performer, title, and geographical catalogs were derived, it was thought best to use that one. Since AFS number is mostly an internally-used reference, though, it isn't a very useful thing to browse by, so there's no explicit "browse" feature.

However, you can more or less browse by finessing the search. An asterisk can be used to replace any string of characters, for example. So, if you want to browse by performer name, you put in

"A*" and you will get all the cards with a performer whose name begins with A. Then you browse through those results. You can do the same for titles.

(And, of course, you can repeat for each letter.)