$ git clone -n https://src.fedoraproject.org/rpms/rubygem-ed25519.git /var/lib/mock/f42-build-865173-172845/root/chroot_tmpdir/scmroot/rubygem-ed25519
Cloning into '/var/lib/mock/f42-build-865173-172845/root/chroot_tmpdir/scmroot/rubygem-ed25519'...
$ git fetch origin b3b61cf532bd34faa428151936bba0b486c3afc1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-ed25519
 * [new ref]         b3b61cf532bd34faa428151936bba0b486c3afc1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b3b61cf Rebuild for https://fedoraproject.org/wiki/Changes/Ruby_3.4