$ git clone -n https://src.fedoraproject.org/rpms/rust-predicates1.git /var/lib/mock/f42-build-side-1-3584761-46896/root/chroot_tmpdir/scmroot/rust-predicates1
Cloning into '/var/lib/mock/f42-build-side-1-3584761-46896/root/chroot_tmpdir/scmroot/rust-predicates1'...
$ git fetch origin e70ea939898dbd8d20988e37ff9eb2609eb0df24:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-predicates1
 * [new ref]         e70ea939898dbd8d20988e37ff9eb2609eb0df24 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e70ea93 compat package no longer needed