Configuration Files - Thunderbird

Configuration Files

userChrome.css

    Used to change the appearance of the browser.

userContent.css

    Used to change the appearance of web pages.

user.js

    Used to change various preferences.

All these files are plain text files you need to create in your profile folder and can be edited using a standard text editor, such as Notepad on Windows and gedit or kate on Linux.

userChrome.css

This file sets the display rules for various elements in the Thunderbird user interface and is located in the sub-folder called chrome in your profile folder. This folder does not exist by default, so you need to create it before you can start adding your preferences.

userContent.css

This file sets the display rules for web content and is located in the sub-folder called chrome in your profile folder. As with userChrome.css, this folder does not exist by default, so you need to create it before you can start adding your preferences.

user.js

This is the additional preferences file for Thunderbird and is located in your profile folder. The file does not exist by default, so you need to create it before you can start adding your preferences. In almost all cases, edits made using the user.js can be done via the Config Editor, which is the recommended method.