Experimental adblock filter list for risky rules

[ShivanKaul]

We'd like to test out risky filter rules before releasing widely. Even after QA, we can't capture all cases of rule-related breakage, especially on fast-moving and complex websites like YouTube. We currently don't have a way of restricting filter rule rollout by channel i.e. we can't say that a filter rule should only get applied in Nightly or Beta as opposed to Release.

As a workaround, we could have an experimental/risky adblock list/component that:

1. Would be default on in Nightly and Beta channels
2. Would be default off in Release, but users will be able to easily opt-in via brave://adblock

This way, we can put in risky adblock rules into this list and try them out in Nightly and Beta, and if everything looks good for a while, we can manually copy them over to the respective adblock list/component that would get sent out to all channels.

When putting in rules to the experimental list, we should make sure to tag @brave/qa-team since by definition these are risky rules that might affect QA testing.

Work Plan:

• Create new list https://github.com/brave/adblock-lists/blob/master/brave-lists/experimental.txt with sample rules. PR: Create experimental.txt adblock-lists#1553
• Generate new component metadata via https://github.com/brave/adblock-resources/blob/master/generate_component.sh
• Upload generated PEM file to 1P and update Jenkins
• Add a new entry for non-default-enabled list in https://github.com/brave/adblock-resources/blob/master/filter_lists/list_catalog.json. PR: Add experimental list adblock-resources#152
• Add brave-core support for enabling new experimental list via Griffin: Add support for enabling experimental list by default brave-core#22858
• Make list default on in Nightly and Beta. PR: brave/brave-variations@c383b68

[ryanbr]

1. Test filter for youtube; A modification from the previous filter that caused issues. Something worthy to test

||googlevideo.com/videoplayback*ctier=L&*%2Cctier%2C from AdguardTeam/AdguardFilters#172976

Could be safe, but I wasn't willing to test again on the possible breakages, given the recent history of the similar filter rule.

2. Another test regarding news.google.com "choppy scroll issues": https://community.brave.com/t/brave-slow-choppy-scrolling-in-google-news/529436/22

[Yuki2718]

Another set of rules worth testing

www.youtube.com##+js(trusted-replace-fetch-response, /"auxiliaryUi":\{"messageRenderers":\{"bkaEnforcementMessageViewModel.*?e\}\}\}\,/, , player?)
www.youtube.com##+js(trusted-replace-fetch-response, /("trackingParam":"kx_fmPxhoPZR)[-_0-9A-Za-z]{150}[-_0-9A-Za-z]+?([-_0-9A-Za-z]{43}BwOcCE59TDtslLKPQ-SS"\})/, $1$2, player?)
www.youtube.com##+js(trusted-replace-xhr-response, /"auxiliaryUi":\{"messageRenderers":\{"bkaEnforcementMessageViewModel.*?e\}\}\}\,/, , player?)
www.youtube.com##+js(trusted-replace-xhr-response, /("trackingParam":"kx_fmPxhoPZR)[-_0-9A-Za-z]{150}[-_0-9A-Za-z]+?([-_0-9A-Za-z]{43}BwOcCE59TDtslLKPQ-SS"\})/, $1$2, player?)

Already added to AG by AdguardTeam/AdguardFilters#172178 and we will eventually add to uBlock filters, just unsure whether yt is no more watching us.

[Yuki2718]

||googlevideo.com/videoplayback*ctier=L&*%2Cctier%2C was added to uBf by uBlockOrigin/uAssets@73a8660 to hopefully mitigate alleged ads slip which we can't figure out yet. Maybe complementary cosmetic can be moved to EL, but no need to hurry up.

[ShivanKaul]

The Experimental list was turned on in Nightly and Beta via Griffin: https://github.com/brave/brave-variations/blob/production/seed/seed.json#L2597, closing this out.