$ git clone -n https://src.fedoraproject.org/rpms/rust-rustls.git /var/lib/mock/f39-build-1512306-35564/root/chroot_tmpdir/scmroot/rust-rustls
Cloning into '/var/lib/mock/f39-build-1512306-35564/root/chroot_tmpdir/scmroot/rust-rustls'...
$ git fetch origin dd1604b817fab2f532848cb68c800480be9259f1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-rustls
 * [new ref]         dd1604b817fab2f532848cb68c800480be9259f1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dd1604b Update to version 0.21.8; Fixes RHBZ#2219880