$ git clone -n https://github.com/fedora-riscv/llvm.git /var/lib/mock/f39-build-1657741-40568/root/chroot_tmpdir/scmroot/llvm
Cloning into '/var/lib/mock/f39-build-1657741-40568/root/chroot_tmpdir/scmroot/llvm'...
$ git fetch origin 4e7ee4b8cc5fddd89d6dee3949a081fdb8b90545:KOJI_FETCH_HEAD
From https://github.com/fedora-riscv/llvm
 * [new ref]         4e7ee4b8cc5fddd89d6dee3949a081fdb8b90545 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4e7ee4b Rebuild for f39