Advanced: Auto-Updates, Bookmarks
app.update.enabled (Boolean). Setting this option to true enables Firefox to check at regular intervals for updated versions of Firefox. Of late the main Firefox releases have been due to security issues and as such it would be recommended to leave this set to true. If you don't require this functionality for some reason, set this to false. Note - This is the same as selecting the Automatically check for updates to - Firefox option in the Advanced, Update tab.
app.update.interval (Integer). The value entered here specifies the amount of time, in seconds, that Firefox waits before checking for updates. The default being 86400, aka 1 day. Of late the main Firefox releases have been due to security issues and as such it would be wise to leave this at the default to ensure you get notified of such updates ASAP.
app.update.auto (Boolean). When set to true (default) this enables Firefox to automatically download and install detected updates. The degree to which updates are installed automatically is determined by app.update.mode. Setting this to false allows you to determine the action to be taken when an update is available, i.e. install or don't install. This is recommended where you want to have control over changes to Firefox, e.g. you may prefer to want on installing updates to ensure no unmentioned compatibility problems arise.
Setting this to false disables the automatic download and installation of detected updates. Note - Firefox can still check for updates regardless of whether this is set to true or false. This is the same as selecting the When updates to Firefox are found - Ask me what I want to do option in the Option menu's Advanced, Update tab.
app.update.mode (Integer). This setting sets how the Automatic Updates features handles updates available for Firefox when app.update.auto is set to true. 2 options are available (Note - This is the same as the When updates to Firefox are found option in the Advanced, Update tab);
0. Selecting this option enables Firefox to automatically download and install any available updates. This is recommended for hassle-free Firefox maintenance and will ensure the latest security and other updates are installed when released.
1. This option specifies that Firefox prompts you where a Firefox update available will break compatibility with any installed Extensions/Themes. In such cases you may wish to wait for a compatible Extension/Theme to be released, or to install the update regardless.
browser.search.update (Boolean). Setting this option to true (Default) enables checking for updated version of installed Search plugins. Set this to false to disable such checks. Note - This is the same as selecting the Automatically check for updates to - Search Engines option in the Advanced, Update tab.
extensions.update.enabled (Boolean). Setting this to true enables checking for updated version of the Extensions/Themes. Set this to false disables such checks, which isn't recommended. Note - This is the same as selecting the Automatically check for updates to - Installed Add-ons option in the Advanced, Update tab.
extensions.update.interval (Integer). The value entered here specifies the amount of time, in seconds, that Firefox waits before checking for updates to installed Extensions and Themes. The default is 86400 (1 day).
Bookmarks
browser.chrome.favicons (Boolean). Many websites feature an icon that can be displayed in the address bar and for any bookmarks created. Setting this to true enables such icons to be displayed, which you might want to do as they add some variety, e.g. the Wikipedia and TechSpot forum bookmarks shown beneath use such icons, whereas the other 2 bookmarks use the default icon as they lack a custom one.
Setting this to false will disable such icons, which can result in smaller bookmarks and minor bandwidth savings as the icons will not be downloaded.
browser.chrome.site_icons (Boolean). This performs a similar function to browser.chrome.favicons and should be set to the same value as that is (As there's 2 different ways in which an icon can be referenced, presumably at some stage these options will be merged).
browser.tabs.loadBookmarksInBackground (Boolean). Setting this option to true specifies that new tabs launched from bookmarks/history are to be loaded in the foreground, while false specifies that such new tabs in the background.