Information
This setting controls whether Firefox's Enhanced Tracking Protection is enabled. Enhanced Tracking Protection will automatically block known third-party tracking cookies.
Rationale:
Allowing third-party cookies could potentially allow tracking of your web activities by third-party entities which may expose information that could be used for an attack on the end-user.
Impact:
Disabling third-party cookies could cause some websites to not function as expected.
Solution
To establish the recommended configuration, set browser.contentblocking.category to true:
Type about:config in the address bar
Type browser.contentblocking.category in the filter
Ensure the setting is set as prescribed.
OR
Open the mozilla.cfg file in the installation directory with a text editor
Add the following lines to mozilla.cfg:
lockPref('browser.contentblocking.category', true);
Default Value:
True (Enabled).