Why does Firefox use the “chrome://” protocol / schema in urls?

When I want to configure an addon, for example Ghostery, the tab shows a URL like this one:

 

chrome://ghostery/content/options.html

What does it mean? Does it have something to do with the Chrome browser?

Solution:

The phrase chrome has been used by Mozilla since long before Google Chrome came on the market. Typically the phrase “Chrome” referred to all the area around your viewport, but not the viewport itself. Sort of like the chrome plating some cars have around their windscreens or headlights.

See here for more details – but no; nothing to do with Google Chrome.