$ git clone -n https://src.fedoraproject.org/rpms/rust-gcd.git /var/lib/mock/f45-build-41779-785/root/chroot_tmpdir/scmroot/rust-gcd
Cloning into '/var/lib/mock/f45-build-41779-785/root/chroot_tmpdir/scmroot/rust-gcd'...
$ git fetch origin 82155acbee162c4cd6a6d412d31668d4ecb17dd6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gcd
 * [new ref]         82155acbee162c4cd6a6d412d31668d4ecb17dd6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 82155ac Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild