This repository is the source for official Firebase Extensions: a Lerna-monorepo of self-contained, event-driven Cloud Functions applications, each packaged with an extension.yaml manifest for installation into Firebase projects. In production the extensions react to Firestore, Realtime Database, Cloud Storage, Auth, Pub/Sub, and scheduled triggers to sync data to BigQuery, send email through SMTP/SendGrid, resize and moderate images, translate document fields, shorten URLs, limit RTDB child nodes, delete user data across Google services, and maintain distributed counters. The firestore-bigquery-export extension is the most data-heavy component and includes a reusable npm package, CLI import tooling, schema-view generators, partitioning/clustering logic, and materialized-view SQL, making the repo a hybrid of serverless application code and data-pipeline engineering. Each extension follows a consistent architecture: a typed env-var config module, structured logging, Eventarc event recording, and a functions/src/index.ts Cloud Functions entry point. The BigQuery exporter is built around a published @firebaseextensions/firestore-bigquery-change-tracker library that handles dataset/table initialization, Firestore-change streaming, schema-lag retries, failed-transaction backup, and latest-snapshot query generation. Companion CLIs support backfilling existing Firestore collections into BigQuery and generating typed BigQuery views, including AI-assisted schema inference via Genkit/Gemini. A distributed counter extension additionally ships web, Android, iOS, Dart, and Node client libraries. The repository is professionally tested with unit, emulator, and gated integration/e2e suites, but it is in a transitional state: the official Firebase Extensions platform is scheduled to shut down in 2027, firestore-bigquery-export is already deprecated in favor of a newer function-kit package, and the codebase mixes firebase-functions v1 and v2, legacy and modern BigQuery SQL paths, and old client toolchains. The overall architecture remains solid and many internal patterns are reuse-worthy, but the deprecation horizon and inconsistent modernization limit its long-term value as a reference implementation.