$ git clone -n https://src.fedoraproject.org/rpms/rust-circular-buffer.git /var/lib/mock/f42-build-3253010-41225/root/chroot_tmpdir/scmroot/rust-circular-buffer
Cloning into '/var/lib/mock/f42-build-3253010-41225/root/chroot_tmpdir/scmroot/rust-circular-buffer'...
$ git fetch origin 3f28cf6ba389b249ec91dd1bb6d9fdae60a62ad1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-circular-buffer
 * [new ref]         3f28cf6ba389b249ec91dd1bb6d9fdae60a62ad1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3f28cf6 Improve a regex in the .rpmlintrc file