What is a 'pool party attack' that tracks users by taking advantage of the privacy function of the browser?

Browsers limit the amount of resources a website can open and consume, and different browsing contexts are consuming resources from the same pool. Therefore, browsers have introduced a feature called 'partitioning' that prevents trackers from tracking users between sites by giving each site a separate set of resources. However, the development team of the web browser Brave explains the 'pool party attack' that exploits this partitioning.

[2112.06324] Pool-Party: Exploiting Browser Resource Pools as Side-Channels for Web Tracking
https://arxiv.org/abs/2112.06324

Preventing Pool-Party Attacks | Brave Browser
https://brave.com/privacy-updates/13-pool-party-side-channels/

Partitioning protects users from cross-site tracking by preventing them from knowing that a tracker on one site is the same as a user on another site. For example, even if both 'site-a.example' and 'site-b.example' contain tracking scripts from 'tracker.example', partitioning will 'visit each site by the same person'. Prevents tracker.example from being noticed and prevents trackers from linking user movements across multiple sites.

There are multiple resources managed by the browser , such as web storage , network, CSS cache, and font cache. The resources that can be partitioned vary from browser to browser and can be checked on the following pages.

PrivacyTests.org: open-source tests of web browser privacy
https://privacytests.org/

A pool party attack is one in which the site side exploits the partitioning of this resource pool, and the attacker manipulates the resources shared between the sites to communicate with each other and track them.

Brave said, 'This pool party attack can be exploited in different ways against all common browsers. Any resource pool shared across site boundaries is used for site-to-site tracking. There is a possibility. '

Brave plans to roll out features for desktop and Android to protect users from pool party attacks, such as unrestricting wideband resource pools to make them aware of attacks. He also said that it will work with other browser developers such as Apple, Google and Mozilla to enable the entire web browser to deal with pool party attacks.

However, according to the social news site Hacker News, 'The impact and countermeasures of the pool party attack are unclear just by reading Brave's article, and the content of the pool party attack is also reclassified as cross-site scripting that was pointed out in the past. It may be an appeal to be praised by the people around me just by doing it. '

I did some digging. To me it was rather unclear about the impact of this. Furthe ... | Hacker News
https://news.ycombinator.com/item?id=29571633