Examine source code of mybluetheme

{
  "name": "mybluetheme",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "annie-spratt-469222-unsplash.jpg"
    },
    "colors": {
      "toolbar": "rgba(222, 222, 222, 0.31)",
      "toolbar_field_text": "rgba(250, 250, 250, 1)",
      "frame": "rgba(110, 135, 189, 0.95)",
      "tab_background_text": "rgba(0, 0, 0, 1)"
    }
  }
}