Access to browse firefox internal icons

[BoomerangAide]

I just discovered that it was possible to browse some of the icons of Firefox by using the url resource://gre/chrome/toolkit/skin/classic/global/icons/
This discovery was thanks to that:

 chrome://browser/skin/ is resource:///chrome/browser/skin/classic/browser/ (/browser/omni.ja)
 chrome://global/skin/ is resource://gre/chrome/toolkit/skin/classic/global/ (/omni.ja)
 chrome://mozapps/skin/ resource://gre/chrome/toolkit/skin/classic/mozapps/ 

Source: https://support.mozilla.org/gl/questions/961818

This may be useful for custom styling, and deserve to be noted here if nowhere else.

This discussion could also be to report other browsable paths to Firefox useful resources if they exist.

edit:

I will also add something from my use of CustomJSforFx

var sheet1 = 'chrome://global/skin/icons/Portrait.png';
var sheet2 = 'file:///' +
Components.classes["@mozilla.org/file/directory_service;1"].getService( Components.interfaces.nsIProperties).get("ProfD", > Components.interfaces.nsIFile).path.replace(/\134/g,'/') +
'/chrome/image/tab_favicon_sheet.png';

In that case, sheet1 accessed an ordinary image from within Firefox, but sheet2 accessed an icon from this project (after all the mysterious crazy text and /chrome/image you are in the folder corresponding to image.
Well the good news is that for those not using JS, it's much simpler in CSS, just need to check some of the css files that access those images to see how it work.