Examine source code of Video Game Heroes

{
  "theme": {
    "images": {
      "theme_frame": "videogameheroes.png"
    },
    "colors": {
      "frame": "#cfcbcb",
      "tab_background_text": "#030303"
    }
  },
  "version": "2.0",
  "name": "Video Game Heroes",
  "manifest_version": 2,
  "description": "The characters from some of your favorite video games are here to defend your browser."
}