$ git clone -n https://src.fedoraproject.org/rpms/kdb.git /var/lib/mock/f40-build-780049-130662/root/chroot_tmpdir/scmroot/kdb
Cloning into '/var/lib/mock/f40-build-780049-130662/root/chroot_tmpdir/scmroot/kdb'...
$ git fetch origin 016efdc02da420cdd4eacb3b7058bd19bcd5d80e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kdb
 * [new ref]         016efdc02da420cdd4eacb3b7058bd19bcd5d80e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 016efdc Fix FTBFS (rhbz#2261270)