$ git clone -n https://src.fedoraproject.org/rpms/rust-cairo-rs0.15.git /var/lib/mock/f41-build-side-1-2769225-32104/root/chroot_tmpdir/scmroot/rust-cairo-rs0.15
Cloning into '/var/lib/mock/f41-build-side-1-2769225-32104/root/chroot_tmpdir/scmroot/rust-cairo-rs0.15'...
$ git fetch origin 3742641640d2a958c491bcbaffa9364958c9bd60:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-cairo-rs0.15
 * [new ref]         3742641640d2a958c491bcbaffa9364958c9bd60 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3742641 compat package no longer needed