$ git clone -n https://src.fedoraproject.org/rpms/rust-serde_yaml.git /var/lib/mock/f39-build-2260241-54392/root/chroot_tmpdir/scmroot/rust-serde_yaml
Cloning into '/var/lib/mock/f39-build-2260241-54392/root/chroot_tmpdir/scmroot/rust-serde_yaml'...
$ git fetch origin fb2b0d5e5106698f6aee4961ebe2c879612c5e2a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-serde_yaml
 * [new ref]         fb2b0d5e5106698f6aee4961ebe2c879612c5e2a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fb2b0d5 Update to version 0.9.30; Fixes RHBZ#2256430