Examine source code of dark&gray 1b30

{
  "name": "dark&gray 1b30",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "Firefoxteema1.png"
    },
    "colors": {
      "frame": "rgba(48, 48, 48, 1)",
      "tab_background_text": "rgba(172, 172, 172, 1)",
      "toolbar": "rgba(27, 27, 27, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(48, 48, 48, 1)"
    }
  }
}