Examine source code of The Ruby Rhino persona

{
  "theme": {
    "images": {
      "theme_frame": "RubyRhinoTop2bcopy_smaller.jpg"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#f7f4f4"
    }
  },
  "version": "2.0",
  "name": "The Ruby Rhino persona",
  "manifest_version": 2,
  "description": "A ruby rhinoceros in the bush-lands, with kind permission from Dean (BGG boardgame account meat) (replaces Ruby Rhino 1)"
}