$ git clone -n https://src.fedoraproject.org/rpms/rust-derive_builder_core0.12.git /var/lib/mock/f41-build-side-1-3124867-39482/root/chroot_tmpdir/scmroot/rust-derive_builder_core0.12
Cloning into '/var/lib/mock/f41-build-side-1-3124867-39482/root/chroot_tmpdir/scmroot/rust-derive_builder_core0.12'...
$ git fetch origin 3b7853ce8cca8233f738654163a205a57f942caf:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-derive_builder_core0.12
 * [new ref]         3b7853ce8cca8233f738654163a205a57f942caf -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3b7853c compat package no longer needed