Add link to Firefox source file.

diff --git a/docs/index.md b/docs/index.md
index edf6a7b71a9aed273b55219d2e846ab8174b5e79..51cb08a2d8a61ae4c9ff8afa0c7ee35f96dd978a 100644 (file)
--- a/docs/index.md
+++ b/docs/index.md
@@ -5313,6 +5313,8 @@ Set and lock preferences.
 
 Previously you could only set and lock a subset of preferences. Starting with Firefox 81 and Firefox ESR 78.3 you can set many more preferences. You can also set default preferences, user preferences and you can clear preferences.
 
+**NOTE** There are too many preferences for us to provide documentation on them all. The source file [StaticPrefList.yaml](https://searchfox.org/mozilla-central/source/modules/libpref/init/StaticPrefList.yaml) contains information on many of them.
+
 Preferences that start with the following prefixes are supported:
 ```
 accessibility.