Examine source code of Serika

{
  "name": "Serika",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "firefoxheader.jpg"
    },
    "colors": {
      "frame": "rgba(37, 37, 37, 1)",
      "tab_background_text": "rgba(220, 219, 207, 1)",
      "toolbar": "rgba(37, 37, 37, 1)",
      "toolbar_field": "rgba(220, 219, 207, 1)",
      "toolbar_field_text": "rgba(37, 37, 37, 1)",
      "tab_line": "rgba(220, 219, 207, 1)"
    }
  }
}