Carbon Visualiser: a privileged prototype looking for a signing path

atipk — Fri, 31 Jul 2026 09:53:24 GMT

Hello everyone,

With Resource Monitor in development , per-tab CPU and RAM are about to become a first-class part of Firefox. I'm raising something separate that happens to read the same data, and that I don't think should live in the browser at all.

What I'm Not Proposing

The resource attribution part of what I built is essentially what about:processes already does, and what Resource Monitor will do better. I'm not proposing to duplicate it. It reads ChromeUtils.requestProcInfo() and uses Services.wm to map processes back to tabs, which came out of my Honours project at Glasgow estimating per-tab carbon output.

The part I don't think Firefox should ship is the carbon conversion itself. It depends on regional grid intensity, hardware assumptions, and a methodology that isn't settled. Putting that in front of every user means shipping a set of contested assumptions with the browser's name on them. An add-on someone installs deliberately can carry those assumptions; Firefox shouldn't have to.

So the category is tools that should live outside Firefox, that only read, and that need data only Firefox has. Today the only route is an Experiment API on Developer Edition with signature enforcement disabled. The docs note that out-of-tree privileged extensions are signed through a separate pipeline via xpi-manifest rather than AMO.

What I'm Asking

Is that pipeline open to anything outside Mozilla, or is it internal by design? And if it is internal, is there any other route for read-only privileged add-ons, or is Developer Edition the end of the road?

Repo: carbon-visualiser-xpi

I also wrote a short doc mapping this to the ideas on the Sustainability wiki: mozilla-alignment.md

topic Carbon Visualiser: a privileged prototype looking for a signing path in Discussions

Carbon Visualiser: a privileged prototype looking for a signing path