Tor Project is resurrecting SecBrowser as Mullvad Browser

FranklyFlawless · August 2, 2026, 5:38pm

Here is the information I have about Base Browser in one of my LLM project notes:

Kimi K2.6:

What Base Browser Is

BB is a logical partition within tor-browser’s commit history, not a standalone product. The base-browser-*-buildN tag marks the end of the BB baseline.

Backported Mozilla security patches (Bug XXXXXXX prefix) — part of the BB baseline

Uplift candidates for upstream Firefox — part of the BB baseline

Reverts of undesirable Firefox patches — part of the BB baseline

Commits prefixed BB NNNNN: — Base Browser (shared by TB + MB)

Commits prefixed TB NNNNN: — Tor Browser only

Commits prefixed MB NNNNN: — Mullvad Browser only

Mullvad Browser rebases from the base-browser-*-buildN tag

Corollary: Any tooling that extracts, catalogs, or verifies BB must operate on the FULL commit range from FIREFOX_TAG to base-browser-*-buildN. Filtering only for ^BB NNNNN: prefixes will silently drop security backports, uplifts, and reverts — producing an incomplete catalog and a meaningless verification.

I am not going to dump every technical detail unless you want to cherry pick against Base Browser commits among multiple Firefox forks.