the browser. Support for XPCOM and XUL add-ons are no longer offered beginning with Firefox 57. HTTPS-only mode Firefox 83 introduced HTTPS-only mode, a security enhancing mode that once enabled forces all connections to websites to use HTTPS. Tags Smart Location Bar Firefox 3 includes a "Smart Location Bar". While most other browsers, such as Internet Explorer, will search through history for matching web sites as the user types a URL into the location bar, the Smart Location Bar will also search through bookmarks for a page with a matching URL. Additionally, Firefox's Smart Location Bar will also search through page titles, allowing the user to type in a relevant keyword, instead of a URL, to find the desired page. Firefox uses frecency and other heuristics to predict which history and bookmark matches the user is most likely to select. Library View, organize and search through bookmarks, tags and browsing history using the new Library window. Create or restore full backups of this data whenever with a few clicks. Smart Bookmark Folders Users can quickly access their most visited bookmarks from the toolbar, or recently bookmarked and tagged pages from the bookmark menu. Smart Bookmark Folders can be created by saving a search query in the Library. Full page zoom From the View menu and via keyboard shortcuts, the new zooming feature lets users zoom in and out of entire pages, scaling the layout, text and images, or optionally only the text size. Zoom settings will be remembered for each site. Text selection improvements In addition to being able to double-click and drag to select text by words; or triple-click and drag to select text by paragraph, Ctrl (Cmd on Mac) can be held down to retain the previous selection and extend it instead of replacing it when doing another selection. Web-based protocol handlers Web applications, such as a user's favorite webmail provider, can now be used instead of desktop applications for handling mail to links from other sites. Similar support is available for other protocols (Web applications will have to first enable this by registering as handlers with Firefox). Add-ons and extensions There are six types of add-ons in Firefox: extensions, themes, language packs, plugins, social features and apps. Firefox add-ons may be obtained from the Mozilla Add-ons web site or from other sources. Extensions Firefox users can add features and change functionality in Firefox by installing extensions. Extension