Examine source code of blue

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "blueGradation",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(160, 216, 239)",
      "toolbar_text": "rgb(45, 85, 99)",
      "frame": "rgb(48, 185, 240)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgba(255, 255, 255, 0.7)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(255, 255, 255)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(0, 0, 0)",
      "tab_loading": "rgb(255, 255, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b9c091e2-729b-4de8-9f9a-1907d32daec1}"
    }
  }
}