The wgVectorGrid configuration flag was used by T312241. It can safely be removed once origin/wmf/1.39.0-wmf.21 is enabled everywhere (At earliest 29th July 2022). Removing the code will lead to better performance (no legacy layout code loaded) and easier to work with code.
The legacy layout CSS was retained for cached HTML. It can safely be removed in origin/wmf/1.39.0-wmf.22 (earliest merge date Tuesday 27th)
- Remove VectorGrid feature flag and associated code
- Remove wgVectorGrid from mediawiki configuration (blocked on TODO #1)
- Remove all instances of .vector-layout-legacy class selector (earliest 27th)
- Replace all instances of .vector-toc-visible with .vector-layout-grid (earliest 27th)
- Remove instances of .mw-workspace-container