$ git clone -n https://src.fedoraproject.org/rpms/rust-derive_builder_core0.9.git /var/lib/mock/f41-build-side-1-3124873-39482/root/chroot_tmpdir/scmroot/rust-derive_builder_core0.9
Cloning into '/var/lib/mock/f41-build-side-1-3124873-39482/root/chroot_tmpdir/scmroot/rust-derive_builder_core0.9'...
$ git fetch origin 3c51cb598cce84f64d9eb99f89fef8fc188c9906:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-derive_builder_core0.9
 * [new ref]         3c51cb598cce84f64d9eb99f89fef8fc188c9906 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3c51cb5 compat package no longer needed