Examine source code of colorful gradient

{
  "name": "colorful gradient",
  "manifest_version": 2,
  "version": "6.0",
  "theme": {
    "images": {
      "theme_frame": "gradient.png"
    },
    "colors": {
      "frame": "rgba(70, 101, 189, 1)",
      "tab_background_text": "rgba(255, 255, 255, 0.75)",
      "toolbar": "rgba(189, 207, 255, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(255, 255, 255, 1)",
      "toolbar_field_text": "rgba(107, 41, 82, 1)",
      "tab_line": "rgba(255, 255, 255, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{41bf732b-f15d-4048-b7d0-f6a533cd8efb}"
    }
  }
}