Firefox has added a new feature in Firefox Nightly that blocks trackers that slow down page loads. Firefox will strip cookies and block storage access from third-party tracking content, based on lists of tracking domains by Disconnect. Future versions of Firefox will block these practices by default by default in Firefox 65. Mozilla will be testing this feature using a shield study in September and will start blocking slow-loading trackers in Firefox 63 by default. Users can control both features from the Control Center menu, accessible on the left-hand side of the address bar.”]
Source: https://blog.mozilla.org/futurereleases/2018/08/30/changing-our-approach-to-anti-tracking/