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


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


2 Answers 2


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.

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    Actually a lot to do with Google Chrome: Google Chrome is explicitly named after the user interface chrome of a browser. In their very first marketing video (or was it the comic?) they explain something along the lines of focusing on reducing the chrome and focus on the content instead or summin’ like that. Dec 10, 2012 at 8:10
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    (Page 24 of the comic) Dec 10, 2012 at 8:17
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    I beg to differ, although the name of Google Chrome is named after the UI component, the chrome part of FF has nothing to do with the chrome browser itself; as the op is obviously asking. Dec 10, 2012 at 9:47
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    I didn’t intend to comment here again but the sheer number of upvotes on your comment surprises me: I mentioned that Google Chrome is named after the UI concept. Clearly this implies that chrome://, which refers to the UI concept as well, doesn’t in fact refer to the Google Chrome browser. At least I thought that was obvious. Now, that isn’t the same as “nothing to do with x”. “nothing to do” implies that there’s no connection – and that’s wrong, there is a connection: both chrome:// and the name of Google Chrome refer to the same UI concept. Dec 10, 2012 at 16:06
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    @Konrad: I see what you're saying, but I think you may be mistaken in thinking that the "has nothing to do with" relation is symmetric. In other words, it is plausible that while the name of Google Chrome has something to do with the chrome:// pseudoscheme in Mozilla, the reverse is not the case.
    – LarsH
    Dec 12, 2012 at 2:13

This is a type of binding in firefox that has existed for some time. Chrome refers to the user interface of the browser. For instance this includes everything outside of the webpage you're viewing.

The chrome:// binding is a feature for developers of extensions and built in Firefox features such as the bookmarks manager or downloads window. You can find a list of these chrome:// mappings here. Basically it is a way for firefox to reference files that are on your computer that however might change due to your install path, operating system, or simply the firefox developers choosing to change the physical folder path. These bindings allow developers to always reference the same location.

There are also some other advantages or differences for developers as outlined here. They include the ability that chrome:// url's are exempt from security restrictions - so they can do more things and interact with your browser. They allow the feature to interact or reference other user parameters that might have changed due to customization of themes or locals (regional or language changes) without having to know exactly what the user's customized settings are.

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