Examine source code of Eye Dropper

{
  "manifest_version": 2,
  "name": "Eye Dropper",
  "description": "Pick colors from any website.",
  "version": "4.10.3.15",
  "icons": {
    "19": "icon/19.png",
    "38": "icon/38.png",
    "48": "icon/48.png",
    "128": "icon/128.png"
  },
  "browser_action": {
    "theme_icons": [
      {
        "light": "icon/light.svg",
        "dark": "icon/dark.svg",
        "size": 16
      }
    ],
    "default_title": "Popup",
    "default_popup": "popup.html"
  },
  "permissions": [
    "activeTab",
    "storage",
    "scripting"
  ],
  "web_accessible_resources": [
    "edropper.js"
  ],
  "commands": {
    "pick-from-webpage": {
      "suggested_key": {
        "default": "Alt+P"
      },
      "description": "Pick color from web page"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "prod@eyedropper.org"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "open_in_tab": true,
    "page": "options.html"
  }
}