How to deal with manually provided/cached catalogues for guide star selection?

The description of https://pfspipe.ipmu.jp/jira/projects/FIBERALLOC/issues/FIBERALLOC-28 mentions:

But also shuffle must allow for other catalogs (sdss, vizier) and manually supplied catalogs (e.g. from HSC pre-imaging).

(emphasis added).

I'd like to understand better what these manually supplied catalogs look like. If they come in form of table names on a TAP-capable server, everything is fine, but if they are supplied as, e.g., FITS files (which was the case for HETDEX, if I understand correctly), I cannot really deal with them at the moment. Querying anything that is not behind an ADQL-capable front end will require quite significant changes and enhancements to the current version of the code.