If you want some privacy when it comes to Web browsing, most browsers offer private modes that don't track the sites you visit. It's not foolproof, though, so Mozilla is working on a version that gives the user more control.

Mozilla's updated Private Browsing "actively blocks website elements that could be used to record user behavior across sites," the company said in a blog post. "This includes elements like content, analytics, social, and other services that might be collecting data without your knowledge."

With such strong settings, some sites might appear broken, but Mozilla said you can unblock sites giving you trouble. "Private Browsing in pre-beta Firefox also has a Control Center that contains important site security and privacy controls in a single place," it said.

Mozilla is asking pre-beta testers to try it out and provide feedback.

Firefox is also getting add-on verification that will ensure the extensions you download won't "create unwanted toolbars or buttons, collect information, change your search settings or inject ads or malware into your device."

Add-on verification will be enforced by default in pre-beta Firefox.

The pre-beta channel is reserved for developers and tech-savvy users who want to provide Mozilla with feedback prior to a full release. Most users should wait for the full launch. Recently, Mozilla rolled out Firefox 40, which got an update for Windows 10, as well as new ad content.