Mozilla will enforce Enhanced Tracking Protection (ETP) as standard practice for all users as part of the default Firefox configuration, from today, and will block known third-party tracking cookies, the company has announced.
The cookies will be cross-referenced with the 'Disconnect' list of known third-party trackers that comprise websites that collect and retain data regarding users' activity across multiple sites or applications.
This feature has been widely-anticipated since Mozilla outlined its plans in January, and has been available for new users since June this year. The feature now, however, concerns a fresh approach to anti-tracking the firm outlined recently based on testing and revision.
Mozilla also previously teased a subscription-based version of Firefox with additional privacy-centric features, which also reportedly featured ETP available as standard.
"Currently over 20% of Firefox users have Enhanced Tracking Protection on. With today's release, we expect to provide protection for 100% of our users by default," Mozilla said.
"Enhanced Tracking Protection works behind-the-scenes to keep a company from forming a profile of you based on their tracking of your browsing behaviour across websites - often without your knowledge or consent.
"Those profiles and the information they contain may then be sold and used for purposes you never knew or intended. Enhanced Tracking Protection helps to mitigate this threat and puts you back in control of your online experience."
The ETP functionality will also work in the background to prevent illicit cryptocurrency mining scripts from draining users' CPU usage and battery power on their devices. This feature has existed in previous beta versions of Firefox but is now available as standard to all.
Users will know ETP is switched on by the appearance of a purple shield icon in the far-left corner of their address bar. This will show when users visit websites on which third-party tracking cookies are being actively blocked.
Firefox will also block fingerprinting scripts - which harvest a sampling of details from users' devices when visiting a particular website - by default. This snapshot of information can then be used to track users across the web.
Users can block fingerprinting scripts if they turn on 'strict mode', with Mozilla also suggesting this protection will be bundled into the default settings in future releases.
Asked whether there's a risk of reducing the user experience by prioritising privacy, a Mozilla spokesperson said: "ETP only blocks third-party tracking cookies from the Disconnect list. First-party cookies that are used by website providers to improve the user experience on their sites are unaffected.
"ETP works in the background to protect users' privacy. We have extensively tested it and, based on the results of that testing, we do not expect that users will run into issues. If users experience unforeseen issues that were not identified during testing, they can hit the "report a problem" link under the "i" icon in the address bar."
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Keumars Afifi-Sabet is a writer and editor that specialises in public sector, cyber security, and cloud computing. He first joined ITPro as a staff writer in April 2018 and eventually became its Features Editor. Although a regular contributor to other tech sites in the past, these days you will find Keumars on LiveScience, where he runs its Technology section.