Examine source code of Elementary Persona

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#a9b7c4",
      "tab_background_text": "#4d4d4d"
    }
  },
  "version": "2.0",
  "name": "Elementary Persona",
  "manifest_version": 2,
  "description": "This Persona is intended to allow Firefox to merge with the awesome Elementary GTK theme."
}