Examine source code of Joe's Test Theme

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#101010",
      "tab_background_text": "#ffff00"
    }
  },
  "version": "2.0",
  "name": "Joe's Test Theme",
  "manifest_version": 2,
  "description": "This is a template to show how themes get applied.\nThe header charcoal has lines at x=1500 and y=100.\nThe footer is magenta and has lines at x=1500 and y=50."
}