Firefox provides settings and configuration windows in a user friendly way. But as a browser it provides a lot of configuration and all of these configurations can not be put in to forms. We can access this detialed configuration through browser address bar.
Open All Configs
We can open about config by putting about:config
into address bar. This will show us a warning about the sensitivity of the configuration page we want to open.

After clicking the button I accept the risk
we will see following screen which will list all configuration.

Search and Filter About Config
As we see there are a lot of configuration parameters. Finding a configuration from this list by searching with eye is very hard. We can use Search
box in the start of the page. In this example we will search for mp4
configuration or term.

Add New Preference
We can add new configuration line simply clicking one of the configuration with right mouse button and selecting one of the type from New
menu
String
is used for text valuesInteger
is used for numeric valuesBoolean
is used logicTrue
andFalse
values

As an example we have selected String
. First we put the value name which is Test
in this case.

Than we put the value of the Test
configuration which is This is test

Preference Status
Most of the preferences comes by default but we can change them. As we see in previous example we can also add new preference. Preference Status
‘s are
user set
is defined or changed by userdefault
is provided by browser.