Documenting that Maintainer addressed this bug in early May, and that the sponsor (I) failed to upload the updated package in a timely manner.
The updated package should be making its way into the archive in the next 24 hours. This might not prevent the package from being removed from testing on May 25th, but it should transition from unstable back into testing in the next 2 weeks. My apologies for any inconvenience this may cause - namely that basex will wink out of existence in testing for a bit. Cheers, tony