$ git clone -n https://src.fedoraproject.org/rpms/rust-derive_builder.git /var/lib/mock/f38-build-side-43-rust-devel-1414287-31447/root/chroot_tmpdir/scmroot/rust-derive_builder
Cloning into '/var/lib/mock/f38-build-side-43-rust-devel-1414287-31447/root/chroot_tmpdir/scmroot/rust-derive_builder'...
$ git fetch origin 54a4bc38701b1b030ec4d40452693fdee5de4bdd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-derive_builder
 * [new ref]         54a4bc38701b1b030ec4d40452693fdee5de4bdd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 54a4bc3 Update to version 0.12.0; Fixes RHBZ#2064470