Thunderbird
Active betaMozilla's mail client, whose chat module includes a Matrix account type built on matrix-js-sdk.
desktop · licence MPL-2.0
- Windows
- macOS
- Linux
- Last commit
- today 4 Nov 2026
- Commits, last year
- 4.1k 1.5k in 90 days
- Authors, 90 days
- 55 90 in a year, 1.5k ever
- Bus factor
- 6 authors making half of last year's commits
- Last release
- RELEASE_160_BASE 4 Nov 2026 · 343 tags in a year
- Lines of code
- 7082k Rust
AI
AI policy
What the project says about AI-made contributions
No policy found (fits the chosen stance)(against the chosen stance)AI in development
Whether the developers use AI tools on the repository
Occasional (fits the chosen stance)(against the chosen stance)Collector: 15 of 4.1k commits in the last year credit an AI tool (0.4 %): claude 13, qwen 2. 1 agent file, 0 AI workflows. A lower bound: most AI use leaves no trace.
- AGENTS.md at the root of the comm repo (a2318b178f)
- 13 of 3,823 commits in the last 365 days carry Claude co-author trailers (0.3 %, repo-wide, not the Matrix module)
-
AGENTS.md(agents.md) -
f7efe527a2026-11-02 claude -
9d6d005762026-10-26 claude -
420f454702026-10-21 claude -
c1a8635782026-10-19 claude -
8305a40f32026-10-19 claude
AI in the product
Whether the product itself has AI features
None found (fits the chosen stance)(against the chosen stance)Activity
Languages
Apps
Features
| Feature | Value | How we know | Evidence |
|---|---|---|---|
| SDK | matrix-js-sdk vendored in chat/protocols/matrix/lib with matrix-sdk-crypto-wasm | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| Encryption (E2EE) | Yes: Yes pattern match [rust-crypto] | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| Cross-signing | Yes: Yes pattern match [cross-signing] | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| Key backup | Yes: Yes pattern match [keybackup] | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| Sliding sync | Not found: Not found | — | — |
| Next-gen auth (OIDC) | Yes: Yes pattern match [oidc] | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| Multiple accounts | Not found: Not found | — | — |
| Threads | Yes: Yes pattern match [threadRoot] | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| Spaces | Yes: Yes pattern match [isSpace] | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| 1:1 calls | Yes: Yes pattern match [m.call.invite] | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| Group calls | Not found: Not found | — | — |
| Reactions | Not found: Not found | — | — |
| Edits | Not found: Not found | — | — |
| Replies | Not found: Not found | — | — |
| Polls | Not found: Not found | — | — |
| Custom emoji | Not found: Not found | — | — |
| Stickers | Not found: Not found | — | — |
| Location | Not found: Not found | — | — |
| Voice messages | Not found: Not found | — | — |
| Rich text editor | Not found: Not found | — | — |
| URL previews | Not found: Not found | — | — |
| Push notifications | Not found: Not found | — | — |
| Private read receipts | Yes: Yes pattern match [ReadPrivate] | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| Presence | Yes: Yes pattern match [presence] | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| Room upgrades | Yes: Yes pattern match [Tombstone] | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| Moderation tools | Yes: Yes pattern match [reportEvent] | code | github.com/thunderbird/thunderbird-desktop/blob/ |
| Accessibility | Not found: Not found | — | — |
| Translations | Not found: Not found | — | — |
| Telemetry | Not found: Not found Mozilla telemetry exists in the wider app; not assessed for the Matrix module | — | — |
| Default homeserver | Not found: Not found | — | — |
| Fork-friendliness | no MPL-2.0; the Matrix code is a module inside the Thunderbird/Firefox tree (40,000+ files in comm alone) | code | — |
Health signals
- Bus factor (last year)
- 6
- Issue first response
- not measured (the forge did not give it)
- Release cadence
- 343 tags in the last year, latest RELEASE_160_BASE (4 Nov 2026)
- CI
- none found
- Tests
- test files found
- Security policy
- none found
- Licence
- MPL-2.0
- Funding
- none listed
- Telemetry SDKs in manifests
- Sentry (taskcluster/docker/tb-updatebot/requirements.txt)
Repositories
| Repository | Role | Activity | Last commit | Commits 1y | Authors 90d | Measured at |
|---|---|---|---|---|---|---|
| github.com/thunderbird/thunderbird-desktop | main | Active | 4 Nov 2026 | 4.1k | 55 | a2318b178 |
Notes
Only chat/protocols/matrix was checked out; features found there by pattern. Activity metrics for this repo describe all of Thunderbird, not its Matrix support. Mozilla-wide AI contribution rules were not checked.
Researched by an AI agent (Claude) on 5 Nov 2026, not checked by a person; metrics collected on 5 Nov 2026. Source file: data/projects/client/thunderbird.yaml. Spotted a mistake? Open an issue with a link.