Start at https://tracker.debian.org/pkg/geda-gaf :
source package has 1 unsatisfiable build dependency
1 binary package has unsatisfiable dependencies
A new upstream version is available: 1.10.0
lintian reports 3 errors and 8 warnings
The package has not entered testing even though the delay is over
Depends on packages which need a new maintainer
Multiarch hinter reports 2 issue(s)
version in VCS is newer than in repository, is it time to upload?
RM: This package has been requested to be removed.
AppStream hints: 2 warnings
Build log checks report 4 warnings
Standards version of the package is outdated.
You can see that the previous package maintainer is no longer maintaining, so contacting them is unlikely to accomplish much.
A new volunteer --or preferably several new volunteers-- are needed to step up, learn the skills, and take over the work.
Debian and Ubuntu are the product of volunteer efforts like that.
It's too late for 20.04 and 20.10: Packages uploaded after release will NOT be backported unless there are exceptional circumstances (like a critical vulnerability). A new volunteer maintainer(s) will need to hustle to get the package buildable for 21.04 before Debian import freeze in a few months.