Most computer users know of Mozilla Firefox because it’s one of the most popular browser’s around. Something a lot of more tech minded people like is the vast amount of configuration options built in and the thousands of extensions to help make it even better in almost every aspect. The more experienced among you will know that like some other browsers such as Chrome, Firefox has hundreds of extra options hidden away from sight and not available in the standard Option dialog windows.
The hidden options page is accessed by typing about:config into the address bar. A warning window will appear telling you that this might void your warranty and changing these advanced settings can be harmful to the stability, security and performance of this application. After clicking the I’ll be careful, I promise button, a page with hundreds of hidden settings will appear.
Most of the settings found in the about:config window are not something you can, or should simply go in and change without prior knowledge of what the setting does. If you do it wrong, chances are websites will load slower than usual, Firefox takes more memory usage, or in the worst cases even crashing your browser. Of course there are some settings which are pretty safe for you to configure because they only do something like change your start page, but unfortunately it’s not always easy to tell which one is safe or not because there are so many with cryptic or hard to decipher names.
After installing the gui:config extension, just click the Firefox button and select Options -> Advanced Settings to access the about:config main interface. It’s worth noting that although gui:config has loads of the options in its interface, this is by no means all of the options found in about:config and only provides options that are safe for the average computer user to play around with.
There is a description of every option that is listed by hovering over it and looking at the bottom of the window. If you’re experiencing problems after playing with some configuration settings without giving it much thought, revert the changes back by clicking the Reset All button. You can also reset each specific option to its default value by right-click on it and choose “Set to default value”. The change takes effect immediately without the need to restart Firefox.
If you want or need to go into the about:config because the gui:config extension hasn’t got the options you want, there are a couple of other extensions to help make your life a little easier.
Unless you know specifically what you’re looking for, it can be a little a but tricky to determine what each option in about:config is and what is does. A handy extension called Config Descriptions helps out by adding an extra column into the about:config window that shows a brief description of many of the displayed options.
What the extension does is simply take the description information provided in the Mozilla about:config entries pages and adds it into the config window in the form of a comment and a tool tip if you hover the mouse over it, this saves you having to manually look up what a function does.
Another useful little tool which can give you more information about an about:config entry that has no description or you don’t recognize, is called PrefSearch. It’s very easy to use and simply adds a right click “Prefsearch” context menu entry in about:config that will search directly in Google for the name of the function. Useful for 3rd party add-ons which won’t have a description in gui:config, Config Descriptions or Firefox itself.