How can you tell?
>A journaling feature has been added for QA purposes.
What exactly does that mean?
point your url bar to about:telemetry
It shows you all the data that has been gathered. (Though IIRC it might still show stuff even when you've disabled telemetry -- in that case the data is being aggregated locally but not sent.)
Go to https://telemetry.mozilla.org
To look at the data on the server side. There are more sophisticated ways of querying it, but obviously not everybody can just be handed access to run arbitrary analysis code.
Probe dictionaries:
https://searchfox.org/mozilla-central/source/toolkit/compone...
https://searchfox.org/mozilla-central/source/toolkit/compone...
https://searchfox.org/mozilla-central/source/toolkit/compone...
How you probably think it works in Firefox and how it actually works in Firefox are two different things, by the way:
https://feeding.cloud.geek.nz/posts/how-safe-browsing-works-...
It's not this convoluted. Give people their privacy.
I argued with someone about how we shouldn’t expect privacy with a cell phone, I don’t see how a 24/7 location tracking device that reads data telemetry (even if you use a custom privacy rom you connect to the towers and send telemetry) can ever be seen as private. PCs are usually compromised with Intel ME or AMD ST (unless you have a specially modded one or use old government contracted ones with them disabled).
It's really apparent when I socks proxy into a remote site (via limited 2G) to view a few kB worth of HTML admin page and firefox starts autoupdating a bunch of remote resources.
Browsers know much more. Most channels are encrypted nowadays so ISP doesn't know what you talk about on internets.