Routes v4 to v5: directory-style canonical URLs¶

Routes v5 adds one optional trailing slash to non-root canonical paths and aliases. This permits adoption of existing documentation websites without renaming their real public URLs. The root remains /; repeated separators, dot segments, backslashes, percent encoding, queries, fragments, and non-ASCII segments remain invalid. /guide and /guide/ remain distinct paths. No redirect or equivalence is inferred: consumers declare any supported alias explicitly and implement it.

The change is owned by foundation.web version 3, shared by Website and Webapp. Use an explicit Composition upgrade to cross that component boundary, then update the consumer-owned routes worksheet to schemaVersion: 5. Existing v4 path values retain their meanings; add a trailing slash only when that is the product's actual canonical URL. Run the selected Composition validators and real route/browser acceptance. No Site-specific mode or alternate resolver is introduced.