Mozilla Firefox has a variety of hidden Easter eggs, configuration settings and diagnostic information hidden away in its internal about: pages. You can access each page by typing about: into the address bar, followed by the name of the page.
The about: pages contain everything from the story of Mozilla’s battle against Internet Explorer and robot pop-culture references to advanced configuration settings, permission management and diagnostic information.
The about:about page is an index of Firefox’s about pages. Click any of the links on this page to explore them yourself.
Many of them are pages you can already access from the user interface — for example, the about:about page shows the same version information as the About window and about:addons just takes you to the add-on management page.
The about:mozilla page contains a verse from the Book of Mozilla.
There’s no full Book of Mozilla, but different verses have appeared on this page in the past. The about:mozilla page first appeared in the Netscape browser in 1994 — this is a long-running Easter egg.
You can read the entire Book of Mozilla — the few verses that have been written, at least — on Mozilla’s website. The Book of Mozilla tells the story of Netscape’s battle against Internet Explorer and how Firefox, originally known as Phoenix, rose from Netscape’s ashes.
About:config is the about: page most geeks have heard of. It provides access to all sorts of internal Firefox options that aren’t exposed in the user interface — it’s the go-to place for tweaking Firefox.
Firefox warns you about this page for a reason. You shouldn’t poke around in here and change these settings unless you know what you’re doing.
The page contains a searchable list of preferences, most of which can’t be changed from Firefox’s options window. Some preferences are even more hidden and won’t appear in this list until you right-click in the list and add a new preference with the appropriate name.
Type about:robots into Firefox’s address bar and you’ll get an Easter egg page with information about robots.
Did I say information? I meant pop culture references. The page references The Day the Earth Stood Still, Futurama, The Hitchhiker’s Guide to the Galaxy, Logan’s Run and other popular, robot-themed media.
Has Firefox crashed on you? You’ll find its crash reports on the about:crashes page. Click a crash report and it’ll be submitted to Mozilla, where you can view information about it.
If you’re struggling with a crash, you can use the information here to figure out what the problem is. Googling up some of the crash messages might help you determine the problem.
Firefox includes website-specific permissions, which you can manage for a single website by right-clicking on a web page selecting View Page Info. About:permissions shows you all this information in one place.
The Permissions Manager shows you each website’s permissions at a glance. Toggle pop-up window, offline storage and location permissions or view the cookies and passwords Firefox is saving for the website.
This is the same page you can access by selecting Troubleshooting Information from the Help menu, but it’s still worth a look. The about:support page provides information you might need to troubleshoot problems with Firefox.
If you’re getting help online, you can use the “Copy all to clipboard” button to copy all the troubleshooting information — including a list of your extensions, modified preferences and graphics driver properties — to your clipboard. If you’re an advanced user, you can use the “Open Containing Folder” button to quickly open your Firefox profile folder.
The about:credits page lists the people who made Firefox what it is today, from developers and documentation writers to testers and website designers. Thanks, everyone.
There’s one super-secret page I didn’t get to; it’s not even mentioned on about:about. The page in question is about:blank — a blank page. It’s useful if you want a blank page as your homepage when you open Firefox, but that’s about it.