Firefox could get an injection of super extra privacy should tests of an enhanced Private Browsing mode prove successful. Currently incorporated in a "pre-beta" version of the browser, the new mode will go a step further by shutting down page elements that might be snooping on your activities.
The "experimental Private Browsing" mode was announced on Mozilla's official blog yesterday, where its benefits are described in detail:
The experimental Private Browsing enhancements ready for testing today actively block website elements that could be used to record user behavior across sites. This includes elements like content, analytics, social and other services that might be collecting data without your knowledge. In some cases, websites might appear broken when elements that track behavior are blocked, but you can always unblock these if you want to view the website normally.
Basically, most "private" modes in browsers just handled the local side of things, preventing information from being stored about your session in your cookies, history or cache. The feature outlined here would go a step further by attempting to clamp down on websites that might collect data on their side of the fence.
I can understand why it's being tested first — it'd be easy to make it too aggressive and kill basic browsing functionality or social media widgets on some sites — but I'm sure with carefull tuning it'll be a nice addition to Firefox's private browsing arsenal. If it proves very successful, similar features could find their way into the likes of Chrome or even Edge.