Visit the articles below to see the documentation for the queries included in the following query suites:
default: queries run by default in CodeQL code scanning on GitHub.
security-extended: queries from default, plus extra security queries with slightly lower precision and severity.
security-and-quality: queries from default, security-extended, plus extra maintainability and reliability queries.
These queries are published in the CodeQL query pack codeql/csharp-queries (changelog, source).
For shorter queries that you can use as building blocks when writing your own queries, see the example queries in the CodeQL repository.