$ git clone -n https://src.fedoraproject.org/rpms/rust-rc2.git /var/lib/mock/f45-build-44321-812/root/chroot_tmpdir/scmroot/rust-rc2
Cloning into '/var/lib/mock/f45-build-44321-812/root/chroot_tmpdir/scmroot/rust-rc2'...
$ git fetch origin 9f8578c4accc8a3d20e88265ddff8fe488897183:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-rc2
 * [new ref]         9f8578c4accc8a3d20e88265ddff8fe488897183 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9f8578c Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild