MPL-2.0 is file-level copyleft, which is the middle position between MIT and GPL: modifications to MPL-licensed files must be published under MPL, and the rest of your work is untouched. It is the licence Firefox ships under, which is why the Firefox-derived builds in this catalogue carry it.
Filed under the SPDX identifier GitHub reports for the repository,
not under what the README claims. NOASSERTION means a licence file
exists that GitHub could not match to an SPDX identifier — read it
before you depend on it.
Why ACTIVE: pushed_at = 2026-08-12 — 2 days, within the 90-day ACTIVE threshold.
Field
Value at this printing
pushed_at
2026-08-12
archived
false
latest_release
v152.0.4-beta.28 · 2026-07-19
license.spdx_id
MPL-2.0
stargazers_count
11100
http_status
200
fetched_at
2026-08-14T09:12:00Z
rubric_edition
2nd, in force
Endpoint: GET https://api.github.com/repos/daijro/camoufox
unauthenticated · 60 req/hr
A live read does not change what is printed above it. The site records that you ran it; what GitHub returned is not kept. The printed state moves only when the register is swept and a new printing is issued. raw JSON
Engine-level patching is the reason this one keeps working when JS-patch stacks stop. The beta tag has been the shipping tag for months; read that as a release policy, not as instability. — ED.
Why ACTIVE: pushed_at = 2026-08-14 — 0 days, within the 90-day ACTIVE threshold.
Field
Value at this printing
pushed_at
2026-08-14
archived
false
latest_release
—
license.spdx_id
MPL-2.0
stargazers_count
23300
http_status
200
fetched_at
2026-08-14T09:12:00Z
rubric_edition
2nd, in force
Endpoint: GET https://api.github.com/repos/brave/brave-browser
unauthenticated · 60 req/hr
A live read does not change what is printed above it. The site records that you ran it; what GitHub returned is not kept. The printed state moves only when the register is swept and a new printing is issued. raw JSON
Why ACTIVE: No repository. The link check returned 200 at 2026-08-14T09:12:00Z, and 200–399 is ACTIVE for a non-repository entry.
Field
Value at this printing
http_status
200
fetched_at
2026-08-14T09:12:00Z
rubric_edition
2nd, in force
Endpoint: HEAD https://librewolf.net/
No repository, so there is no API field to re-read from a browser. A cross-origin liveness check has to be made server-side; this entry's status comes from the register's own sweep.
The obligation follows the file rather than the program. If you modify a source file that arrived under MPL-2.0, that file stays under MPL-2.0 and you publish it. If you add new files of your own and combine them into a larger work, those files are yours to license as you choose, and the combined work may be proprietary.
That boundary is what makes MPL the practical licence for a browser engine: it keeps improvements to the engine itself in the open without dictating terms to everything built alongside it.
Why it shows up on browser forks specifically
A fork inherits the upstream licence for the files it inherits. The Firefox-derived entries in this catalogue are MPL-2.0 because Firefox is, and the practical consequence for a reader is that their engine-level modifications — which are precisely the interesting part of an anti-detect fork — must be published.
This register reads the identifier from the repository's own licence metadata at the field check, not from a README badge, and prints it exactly as the API returned it.
Questions about the MPL-2.0 entries
Licence questions, answered from the field this register reads and from the licence texts themselves. Nothing here is legal advice.
Is MPL-2.0 copyleft?
Yes, at file level. Modified MPL files stay under MPL and must be made available; new files you add and the larger work you combine them into are not covered. This catalogue groups it in the copyleft bucket for filtering, but its reach is much narrower than GPL-3.0.
Can I combine MPL-2.0 code with proprietary code?
The licence is written to permit exactly that, provided the MPL-covered files themselves remain under MPL and are made available. That is the design intent of file-level copyleft.
Why do the Firefox-based anti-detect browsers use MPL-2.0?
Because they inherit it. A fork carries the upstream licence on the files it inherits, and Firefox is MPL-2.0. The practical effect is that engine-level fingerprinting changes in those forks have to be published, which is why they can be read at all.
Every row above was chosen by somebody who then had to establish two
separate things — whether the code was alive, and whether it was theirs
to use. Donut Browser answers the second in its own repository: an
open-source anti-detect browser under AGPL-3.0, with the desktop
application and the sync server both in that repository, engine-level
fingerprint spoofing through the Wayfern Chromium fork rather than
injected JavaScript, a local REST API and MCP server on your own
machine, zero telemetry, and a pre-launch gate that refuses to start a
profile when the proxy's exit geography contradicts the profile's
fingerprint. Its own licence row is in
this same catalogue, read at the same
field check as everything else.