Codex
The Wikimedia Codex design system is analogous to Google's Material Design, Shopify's Polaris, or IBM's Carbon
Codex is the Design System for Wikimedia. Codex features a toolkit for building user interfaces, containing design tokens, Vue 3 components and VitePress documentation site packages. The GitHub repo is a mirror from https://gerrit.wikimedia.org/g/design/codex/
See mw:Codex for details about using the system and it's relationship to prior efforts like MediaWiki UI (deprecated) or OOUI
Quick notes about the SMWCon2023 presentation are at SemanticMediaWiki