This is very useful for developers who are always using the 'View source' function. This tweak allows you to view the source code of a given website in an external editor. There are two configurations that need to be made.
1. Type 'about:config' into the Address bar 2. Search for 'view_source.editor.external' 3. Change the value to 'True' 4. Now, search for 'view_source.editor.path' 5. Insert the file path to your editor (example: C:\Program Files\notepad++\notepad++.exe)