Multi-brand libraries in Taiwan’s retail and fintech groups often share foundations while each brand overrides a handful of colors. Removing a legacy spacing token without a bridge period breaks marketing landing pages that never migrated.
Our governance playbooks use a three-step deprecation: announce with a replacement mapping, dual-export for one release cycle, then fail CI on the old name in new pull requests only. Existing call sites get a scheduled codemod window, not a surprise red build on a Friday.
Performance intersects here too: obsolete tokens sometimes keep obsolete CSS bundles alive. Cleaning the token graph is part of keeping the design system honest about what still ships to devices.