PUBLIC MARKS from decembre with tags document & interface

You can inspect the Firefox user interface directly with DOM Inspector. (Which is not the same Inspector as in the Web Developer menu.) [addons.mozilla.org] https://addons.mozilla.org/en-US/firefox/addon/dom-inspector-6622/Click the icon in the upper-left corner of DOMi, the one with a pointer on it, then click anywhere in the browser to select an element; that element will be highlighted in the left column. Right-click the highlighted entry to display a context menu: "Copy Selector" suggests selectors for the element, "Set Pseudo-classes..." lets you switch on :hover. Notice that the browser itself is a document with its own URI, chrome://browser/content/browser.xul, Most of the browser chrome is XUL, but some, such as the Stylish editor, is HTML embedded in XUL. https://developer.mozilla.org/en-US/docs/XUL