$ git clone -n https://src.fedoraproject.org/rpms/rust-assert_fs.git /var/lib/mock/f39-build-2259342-54364/root/chroot_tmpdir/scmroot/rust-assert_fs
Cloning into '/var/lib/mock/f39-build-2259342-54364/root/chroot_tmpdir/scmroot/rust-assert_fs'...
$ git fetch origin 2b5f79ecf4c719a4254d4b864b13f2e9eac7832a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-assert_fs
 * [new ref]         2b5f79ecf4c719a4254d4b864b13f2e9eac7832a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2b5f79e Update to version 1.1.1; Fixes RHBZ#2258005