What it does. A plugin marketplace named “mattpocock”, owned by Matt Pocock, that lists one plugin, “mattpocock-skills”, with source “./” (the repo root), a description, the category “engineering”, and keywords. It has no version field.
Why it’s here. The README’s Codex and Copilot install commands (codex plugin marketplace add mattpocock/skills, copilot plugin marketplace add mattpocock/skills) add this marketplace. CLAUDE.md says “.claude-plugin/marketplace.json is the repo’s own marketplace. Every agent except Claude Code installs from it to get automatic updates”. ADR 0002 notes that Claude Code’s official listing does not depend on it.