Hello,
I know here are a lot of talks about WebRTC leak and some others. But guys, you are missing a lot more.
So here are a list which aims to block core Firefox features, which actively leak data to third-party services (as opposed to attempts of sites to track you or otherwise passively collect information). As it isn't always easy to draw a strict line, the most critical passive data faucets like WebRTC are also mentioned.
To change the settings open
about:config.
Google Safe Browsing
Leaks the browsing history to Google. Note that disabling Safe Browsing exposes you to a risk of not being stopped from visiting malicious or phishing sites.
browser.safebrowsing.enabled = false
browser.safebrowsing.downloads.enabled = false
browser.safebrowsing.malware.enabled = false
Firefox stats collecting
Stability and performance reports.
datareporting.healthreport.service.enabled = false
datareporting.healthreport.uploadEnabled = false
Usage statistics.
toolkit.telemetry.unified = false
toolkit.telemetry.enabled = false
Encrypted Media Extensions (DRM)
A binary plugin (closed-source) is shipped with Firefox since v38. It enables playback of encrypted media and lets you use e.g. Netflix without Microsoft Silverlight. To completely remove the plugin you would have to install an EME-free build of Firefox.
media.eme.enabled = false
media.gmp-eme-adobe.enabled = false
Firefox Hello
Firefox connects to third-party (Telefonica) servers without asking for permission.
loop.enabled = false
Pocket integration
A third-party service for managing a reading list of articles.
browser.pocket.enabled = false
Search suggestions
Everything you type in the search box is sent to the search engine. Suggestions based on local history will still work.
browser.search.suggest.enabled = false
WebRTC
Leaks the real IP when using
VPN/TOR. Description and demo.
media.peerconnection.enabled = false
Instead of completely disabling WebRTC you could also make it connect over the default route only using:
media.peerconnection.ice.default_address_only = true
Geolocation
geo.enabled = false
Adobe Flash
plugin.state.flash = 0
I hope this will help to someone..