about Firefox (ENG)

This article has been originally published in Italian (here). Feedbacks on content and translation are appreciated. Contributions are welcome. The original article must be considered the reference in case of updates.

In the “browser war”, whatever statistics tell, my winner is always Firefox. Since release 1.something I have always taken great care to accommodate the red panda on all the computers I use. After this “love declaration” that would please WWF so much (at least until it is not clear that I am talking about software rather than an endangered furry ball), I come back on topic showing some interesting features that I have discovered through years of (intensive) use.

In particular the several “about:” protocols (described in the Mozillazine page) provide us information and tools to dick around on the Web in the best possible way. Well, um…, I also use it for serious things sometimes, a few of them but anyway… 🙂

OK! First of all type “about:about” (without quotes) in the address bar to gaze the list of all available tools. There are quite a lot of them and all belong to Firefox (that is, not brought in by any installed add-on). There is something to suit all tastes, from web development to system information on to the credits and the logo. Introductory description makes it clear right away: not all tools are for normal people. That’s why I’ve put some warning marks! 🙂


Page about:about (alto = high, medio = medium, basso = low)

Note: At the time of writing the new Firefox 29 has been released. It adds a few more protocols to the list. The new items mostly belong to the NSFN list (see below) therefore I am not covering them now.

NSFN (Not Safe For Noobs)

Tools with the red mark should be readily ruled out; have a look if you’re curious although you are not likely to find anything useful – or understandable:

  • buildconfig – options and configuration set when source code was compiled into the files you have downloaded – only for open source sommeliers;
  • compartments – currently running objects related to JavaScript and related memory taken. No worries, they won’t snap at your throat 😉
  • crashes – information on, well…, crashes. Usually there is not much to see here, if you know what I mean.
  • healthreport – information on performances. When active it collects and shares data. Sharing can be disabled in the related about page. You might find some “user facts” in here, for example the totale usage time and the startup time. The first figure is meaningful to users rather than to Mozilla: my figures here are alarmingly high…
  • sync-log / sync-progress – result of synchronizations (if Sync is active and configured). Useful only if Sync doesn’t work (it happens sometimes…)
  • telemetry – “on the filed” data on performances and usage. Mozilla collects this information (if user enables the service) to analyse and improve Firefox. You can disable the service in the related page. For the laymen the whole pages is just techno-babble

Menu Firefox → Options → Advanced

“Well, ok, if you say so…”

Moving on to something less geeky and more useful to the average web surfer. Many of these about have the yellow mark but they’re not to be feared. Indeed, the about I am about ( 🙂 ) to list have even some sort of practical use!



about:memory – Total used RAM

The “bête noire” of all browsers: memory consumption. Five or six open tabs and a couple of add-ons are a common scenario, whatever the browser is: you can’t expect all this comes “for free”.

That’s where about:memory weighs in, a page showing in detail RAM usage: total amount, by page and by objects loaded in each page, all laid out in a tree structure.

Whatever the resource hog, we can find out here and get rid of it (if possible).

Down to the bottom of page you’ll see a “Minimize memory usage” button that removes JavaScript elements and pages not correctly unloaded from memory at tab closure, forcing the so called “garbage collection” (GC – JavaScript objects) and “cycle collection” (CC – web page elements).

firefox_memory_minimizeIf you still have lots of used RAM after an extended web surfing session, despite few tabs left open, that’s the time to try this. Or to shut down your pc and get some fresh air.

A couple of links for further details: Extreme Tech and Mozilla Developer Network. Just pretend you’ve read them.


Wanna see Firefox make somersaults while speaking Sanskrit? Mess around in here and you’ll be satisfied. Everything Foxy can or cannot do, how and why it has to run, including add-on settings, is here. Some items listed here are actually settings you can manage from Preferences, some others (somehow more “technical”) can be modified only from here.

When any tutorial brags about optimizing/speeding up/lighten Firefox, it will surely list a bunch of options found in about:config to be tweaked, more or less the same ones since the very first releases. The complete list of options and the related damage they can cause is in the Mozillazine (here and there).

I also want to brag a little about a super-cool tweak to improve Firefox: set option browser.search.openintab to true in order to have search results (from the search box query) in a new tab instead of the current one. In your face you geeks of stinky tutorials!

firefox_ripristinaAaand… if you finally achieved the major task of fu**ing everything up in the config, just head to about:support as soon as you have stopped swearing and look for the ass-saving button “Restore Firefox…”, that will take you back to your pre-swearing condition. The rest of page content is techy slang for nerds.


firefox_permissions_geolocPrivacy, oh Privacy, where art thou? Mostly here. Even though from Options → Privacy you can enable the “anti-tracking”, a more detailed control can be attained visiting this “about“. For each available items you can decide the global (All sites) or page-specific behaviour. Selecting a single site from the list you can even see how many cookies and password related to the page are stored in the browser and manage (delete!) them.


With Sync active, this page lists the synched tabs from other sessions (other device where Firefox/Sync are used). Basically endless, device- and OS-agnostic dicking around the web.

The other ones are your homework: your 1000-word paper is due on Monday and don’t copy from Whiskypedia!

Choose difficulty level: ► Easy _ Medium _ Hard

That is: anything you’ve already seen and you didn’t know it was an “about”. Bonus: a bit of nerd humour from Firefox developers.

  • about:downloads – list of downloaded files (Oh really? What a surprise! :-D)
  • about:sessionrestore – tabs to be restored after a crash (“Oops! That’s embarassing”)
  • about:addons and about:preferences – that is, installed add-ons and preferences dialog
  • about:newtab – mmmhhh… the “new tab” page including most visited sites quicklinks (optional)

The most trivial one are left to your curiosity.

Just for fun: two special guests in the big list are about:robots and about:mozilla. I won’t say more about these except “Go see these already!”. Be sure to report back how many quotes did you get in the little robot page. Last but not least, the story of “The book of Mozilla” is here.


firefox_webdevtoolsEnough with about pages, let’s move on to some tools that, although useless to the majority of users, are quite cool to waste some more minutes of your er… working time.

Quick, move your little computer rodent to the Firefox menu and… watch the picture here aside. Did I spoil the surprise?

One click here, another one there, you’ll get a small frame below the open page. The “web development” tools let you analyse the content of a web page, view the code and pull a couple more stunts 🙄 ok, “etc. etc.”, but what are these for?

You might be tempted to shout “Who cares?” or “Meh!” all the way, but before you do, please notice that little mostly harmless cube on the right. Found it? Click on it and WOW!

The magic of 3D  without those obnoxious glasses!!!


Have you ever thought how much stuff makes up a web page? Literal layers of connections and references of any kind for each element, visualized here thanks to the 3D. Placing the cursor over the several levels of each object you get its function and the code that creates. Well, if you are  webdeveloperz. Otherwise, you’ll just spend half an hour turning around pages to see “what’s behind”.


Keep the left mouse button pressed to rotate or right one to move (pan), scroll wheel to zoom.

And that’s all, folks! Have a nice surfing (as soon as you are done whirling the whole Internet).

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