Why can't the Cache Size Variables be changed via the FF Options? This Feature was available in Older Versions!
The Subject Line says what I need to say!
Opaite Mbohovái (1)
Current Firefox releases use automatic cache management (browser.cache.disk.smart_size.enabled). You will have to modify related browser.cache.disk prefs directly on the about:config page if you do not want to use the defaults.
You can open the about:config page via the location/address bar. You can click the button to "Accept the Risk and Continue".