Doxygen 1.8.18 fails to process the Wikibase code base and I have verified the issue has been fixed in 1.8.19. This task is to rebuild the doxygen Debian package from operations/debs/doxygen for Buster and have it published to apt.wikimedia.org under:
buster-wikimedia | component/ci |
The related Gerrit change is: https://gerrit.wikimedia.org/r/c/operations/debs/doxygen/+/621291/4 which imports Debian tag 1.8.19-1 and has config switch added to accommodate a difference between LLVM 7 (Buster) and LLVM 11 (unstable).