Examine source code of Oil Rainbow City

{
  "theme": {
    "images": {
      "theme_frame": "oilyblue.png"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Oil Rainbow City",
  "manifest_version": 2,
  "description": "My first theme; very eye-catching. Inspired by the colours of the rainbow. Looks like it was oil-painted"
}