Add example of user pref

diff --git a/README.md b/README.md
index acf671da2321511b460231b1622079767e17eb83..c3341ffe133a3752e554fc6e14fd97fef9a9b48e 100644 (file)
--- a/README.md
+++ b/README.md
@@ -4240,7 +4240,7 @@ Default preferences can be modified by the user.
 
 If a value is locked, it is also set as the default.
 
 
 If a value is locked, it is also set as the default.
 

-User preferences persist across invocations of Firefox. It is the equivalent of a user setting the preference. They are most useful when a preference is needed very early in startup so it can't be set as default by policy.
+User preferences persist across invocations of Firefox. It is the equivalent of a user setting the preference. They are most useful when a preference is needed very early in startup so it can't be set as default by policy. An example of this is ```toolkit.legacyUserProfileCustomizations.stylesheets```.

 
 User preferences persist even if the policy is removed, so if you need to remove them, you should use the clear policy.
 
 
 User preferences persist even if the policy is removed, so if you need to remove them, you should use the clear policy.