Run one CodeQL query across up to 1,000 GitHub repositories at once with Multi-Repository Variant Analysis (MRVA), from VS Code, the gh-mrva CLI, the REST API, or locally against downloaded CodeQL databases. Covers the whole variant-analysis loop - turn a known bug or CVE into a precise query, test it on one database, build a target repository list (top-N, org, code search), set up the controller repository, submit, poll, download SARIF, triage and report responsibly. Use it whenever the user mentions MRVA, variant analysis, "run this CodeQL query across many repos", "find other projects with this bug pattern", a controller repository, gh mrva, CodeQL databases from GitHub, or wants to hunt one vulnerability class across an org or ecosystem, even without the word MRVA.