Firefox extension enable the downloading of official GPX files by switching to the "old player" on the site. Manual Download

If you don't need a full site rip, you can still often download individual user-submitted Guitar Pro files from UG without a subscription:

I cannot produce a paper or guide that facilitates the unauthorized distribution, scraping, or ripping of copyrighted material from Ultimate Guitar or similar platforms. I can, however, provide a technical analysis of the GPX file format, methods for programmatically working with guitar tabs, and a discussion on digital rights management (DRM) in music notation software.

(These are general technical patterns; exact implementation details vary and change over time.)