Examine source code of Chromium Mobile

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Chromium Mobile",
  "manifest_version": 2,
  "description": "A theme that looks like Chromium on Android, made for Firefox for Android.  Unfortunately, due to the way themes are built, the first curve is cut out."
}