Control: tags -1 + upstream This *is* an upstream bug, as the upstream README.md has build instructions for Ubuntu that list libexiv2-dev (no version constraint given) as a required package.
As far as I can tell, it's unaddressed as of the current tip of the master branch. I don't see that anyone has reported it as an issue on GitHub either. (I don't want a GitHub account, so I won't report it myself.) My only interest in this bug is that it has kept nomacs out of bullseye; I don't need its EXIF support. If this package isn't effectively orphaned, perhaps the maintainer can lower the bug's severity? (And/or forward the report upstream...)