Examine source code of ThunderBird_3

{
  "theme": {
    "images": {
      "theme_frame": "Thunder3.jpg"
    },
    "colors": {
      "frame": "#7a7878",
      "tab_background_text": "#0d0c0c"
    }
  },
  "version": "2.0",
  "name": "ThunderBird_3",
  "manifest_version": 2,
  "description": "Anime girl"
}