Using Firefox I'm seeing anti-tracking requests before initial connection

[Nooshu]

Testing a site using Tester: London-89.107.60.22, Firefox on a 3G connection I've started to see tracking protection requests before the initial connection is established. These are to the following URL: https://tracking-protection.cdn.mozilla.net/block-flashsubdoc-digest256/. This has happened while testing both 3G and 3G Fast.

An example of the waterfall I'm seeing can be seen below:

Links to example tests where they can be seen are below:

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[soulgalore]

Yeah, we see this too, here's an example:
https://webpagetest.org/result/191202_AQ_840979ea2e9aa55654756806b1a8a46f/1/details/#waterfall_view_step1

I think something changed in Firefox settings between releases. @stephendonner can you help us in the right direction?

[soulgalore]

This seems to map in time when Enhanced Tracking Protection was turned on by default?

[Nooshu]

This seems to map in time when Enhanced Tracking Protection was turned in by default?

Yes I believe it was around the same time that this was rolled out (version 69).

[pmeenan]

It's a bit of a heavy hammer but I added os-level blocking for the tracking list domains since none of the prefs seem to actually block it. While I was in there I also fixed the "waiting" time for the Firefox waterfalls.

Should look a lot better now: https://webpagetest.org/result/191203_FA_8dcdee9a8d99d4c7e6100eb0a651ee5d/1/details/#waterfall_view_step1