How to hide "site id" icon in firefox address bar?

Question

User interface

Actually, the lock icon to the right of https:// is annoying.
Sometimes it's a modest padlock, and sometimes it's a bold white rectangle with green text inside. for example: www.apple.com
I wanted to open chrome://browser/content/browser.xul, then calculate the element through the inspector and set opacity: 0 for it, but I could not find its id.