Examine source code of Polarr Plugin: Edit Any Photo on the Internet

{
  "name": "Polarr Photo Editor",
  "short_name": "Polarr",
  "description": "Professionally edit any photo on the internet with one click. Works offline.",
  "version": "5.1.1resigned1",
  "manifest_version": 2,
  "minimum_chrome_version": "62.0",
  "requirements": {
    "3D": {
      "features": [
        "webgl"
      ]
    }
  },
  "permissions": [
    "https://photoeditor.polarr.co/",
    "activeTab",
    "contextMenus",
    "tabs",
    "notifications",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://photoeditor.polarr.co/*",
        "<all_urls>"
      ],
      "js": [
        "js/content.js"
      ],
      "run_at": "document_idle",
      "all_frames": false
    }
  ],
  "web_accessible_resources": [
    "js/inject.js"
  ],
  "browser_action": {
    "default_title": "",
    "default_icon": "img/icon/128.png"
  },
  "icons": {
    "128": "img/icon/128.png",
    "256": "img/icon/256.png",
    "512": "img/icon/512.png",
    "1024": "img/icon/1024.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "@firefox"
    }
  }
}