$ git clone -n https://src.fedoraproject.org/rpms/rust-xcb.git /var/lib/mock/f40-build-2270159-54793/root/chroot_tmpdir/scmroot/rust-xcb
Cloning into '/var/lib/mock/f40-build-2270159-54793/root/chroot_tmpdir/scmroot/rust-xcb'...
$ git fetch origin 73b3f8dc74c6131a900612e0bf5620c5e1b936c4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-xcb
 * [new ref]         73b3f8dc74c6131a900612e0bf5620c5e1b936c4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 73b3f8d Update to version 1.3.0; Fixes RHBZ#2253775