Mozilla wants to make private browsing truly private.

The company is testing enhancements to private browsing in Firefox designed to block website elements that could be used by third parties to track browsing behavior across sites. Most major browsers, Firefox included, have a "Do Not Track" option, though many companies do not honor it.

Mozilla's experimental tool is designed to block outside parties like ad networks or analytics companies from tracking users through cookies and browser fingerprinting.

It's available in the Firefox Developer Edition on Windows, Mac and Linux, and Firefox Aurora on Android, Mozilla said Friday.

The tool is in prebeta, although it might be incorporated into future versions of Firefox's main browser.

The tool might cause some data-hungry websites to not load properly, Mozilla said. Users can unblock specific websites if they wish.