there are undeclared file conflicts between gnat-13-<triplet> and gnat-{9,10}-<triplet> in sid. (but not between -9- and -10-).
Maybe it would be sufficient to rebuild the package against gcc-13
13.2.0-13 which had some gnat conflict fixes.
The conflicting files e.g. for gnat-13-aarch64-linux-gnu on amd64 are