Nowadays this should be 'just' running:
- ./branch.py REL1_37 --bundle base --branchpoint master (branch tarball extensions and skins)
- ./branch.py REL1_37 --core --branchpoint master --core-version 1.37.0-beta --task T289586 (branch MW itself and make a sub-module commit)
- ./branch.py REL1_37 --bundle '*' --branchpoint master --core-version 1.37.0 (branch all other extensions and skins)
… I think.