Examine source code of Kaleidoscope II

{
  "name": "Kaleidoscope",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "coloured.theme.bkg.jpg"
    },
    "colors": {
      "frame": "rgba(229, 230, 232, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "bookmark_text": "rgba(0, 0, 0, 1)",
      "tab_line": "rgba(255, 255, 255, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{493dd146-4f49-4a9e-9574-3cdef8d5b365}"
    }
  }
}