$ git clone -n https://src.fedoraproject.org/rpms/rust-derive_builder_core.git /var/lib/mock/f38-build-side-43-rust-devel-1412056-31437/root/chroot_tmpdir/scmroot/rust-derive_builder_core
Cloning into '/var/lib/mock/f38-build-side-43-rust-devel-1412056-31437/root/chroot_tmpdir/scmroot/rust-derive_builder_core'...
$ git fetch origin 896b1e12893eb7818b127bc40b8eac05965b74d5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-derive_builder_core
 * [new ref]         896b1e12893eb7818b127bc40b8eac05965b74d5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 896b1e1 Update to version 0.12.0; Fixes RHBZ#2064471