$ git clone -n https://src.fedoraproject.org/rpms/swift-lang.git /var/lib/mock/f38-build-side-42-init-devel-1280052-30668/root/chroot_tmpdir/scmroot/swift-lang
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1280052-30668/root/chroot_tmpdir/scmroot/swift-lang'...
$ git fetch origin 52cfd81902d1f9785bba6873a428263c2d9c1f24:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/swift-lang
 * [new ref]         52cfd81902d1f9785bba6873a428263c2d9c1f24 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 52cfd81 Updated to Swift-5.8.1-RELEASE