$ git clone -n https://src.fedoraproject.org/rpms/rust-glib-sys0.19.git /var/lib/mock/f42-build-side-1-3502139-45977/root/chroot_tmpdir/scmroot/rust-glib-sys0.19
Cloning into '/var/lib/mock/f42-build-side-1-3502139-45977/root/chroot_tmpdir/scmroot/rust-glib-sys0.19'...
$ git fetch origin c82b2a278b81370e56aa440ca03d9b12290b38ba:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-glib-sys0.19
 * [new ref]         c82b2a278b81370e56aa440ca03d9b12290b38ba -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c82b2a2 compat package no longer needed