$ git clone -n https://src.fedoraproject.org/rpms/rust-url1.git /var/lib/mock/f42-build-3251811-41222/root/chroot_tmpdir/scmroot/rust-url1
Cloning into '/var/lib/mock/f42-build-3251811-41222/root/chroot_tmpdir/scmroot/rust-url1'...
$ git fetch origin dc6f57e92f843f2dd402dd9b2e4e01c653555b54:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-url1
 * [new ref]         dc6f57e92f843f2dd402dd9b2e4e01c653555b54 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dc6f57e compat package no longer needed