$ git clone -n https://src.fedoraproject.org/rpms/rust-tower-layer.git /var/lib/mock/f45-build-45581-824/root/chroot_tmpdir/scmroot/rust-tower-layer
Cloning into '/var/lib/mock/f45-build-45581-824/root/chroot_tmpdir/scmroot/rust-tower-layer'...
$ git fetch origin f1d43e6205214d1b2e048766b9649f4e0d037a5c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-tower-layer
 * [new ref]         f1d43e6205214d1b2e048766b9649f4e0d037a5c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f1d43e6 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild