$ git clone -n https://src.fedoraproject.org/rpms/rust-libm.git /var/lib/mock/f45-build-42932-797/root/chroot_tmpdir/scmroot/rust-libm
Cloning into '/var/lib/mock/f45-build-42932-797/root/chroot_tmpdir/scmroot/rust-libm'...
$ git fetch origin bbb7cf44f951eb61ee3318cb3981aec1e9f7003d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-libm
 * [new ref]         bbb7cf44f951eb61ee3318cb3981aec1e9f7003d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bbb7cf4 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild