Examine source code of Bumblebee_Bourdon

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#274828",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Bumblebee_Bourdon",
  "manifest_version": 2,
  "description": "From a photograph taken in my garden, years ago during the summer. I worked with GIMP, using Liquid Rescale.\nThis is my first Mozilla Theme, i hope that you like it  :o)"
}