$ git clone -n https://src.fedoraproject.org/rpms/rust-trust-dns-resolver.git /var/lib/mock/f42-build-3251775-41222/root/chroot_tmpdir/scmroot/rust-trust-dns-resolver
Cloning into '/var/lib/mock/f42-build-3251775-41222/root/chroot_tmpdir/scmroot/rust-trust-dns-resolver'...
$ git fetch origin fbb086b3afaa20f8d0a3eb87cc70ada44cae1d61:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-trust-dns-resolver
 * [new ref]         fbb086b3afaa20f8d0a3eb87cc70ada44cae1d61 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fbb086b no longer needed