Examine source code of Flat Style Invisibar

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Flat Style Invisibar",
  "manifest_version": 2,
  "description": "Intended for Firefox for Android, this theme exactly blends the main body of the address bar with the accent color behind the bookmark and menu buttons. This produces a pleasing flat look, if you like that sort of thing. A screenshot is visible here:\n<a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/cb8c57827d995f97042ab4b2aeb8985d69a8e8efb9ebc4c5f8e39785fd96d199/https%3A//veuwer.com/i/32ew.png\">https://veuwer.com/i/32ew.png</a>"
}