Examine source code of Night_Bridge

{
  "theme": {
    "images": {
      "theme_frame": "bridge_header.JPG"
    },
    "colors": {
      "frame": "#3d3737",
      "tab_background_text": "#bbbfac"
    }
  },
  "version": "2.0",
  "name": "Night_Bridge",
  "manifest_version": 2,
  "description": "*Bridge as seen from highway at night, some brake lights ahead as I approach*"
}