Examine source code of Easyleadin

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "version": "1.0.14",
  "icons": {
    "16": "assets/icon-16.png",
    "32": "assets/icon-32.png",
    "48": "assets/icon-48.png",
    "64": "assets/icon-64.png",
    "128": "assets/icon-128.png"
  },
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "dev@easyleadin.com"
    }
  },
  "permissions": [
    "notifications",
    "alarms",
    "storage",
    "unlimitedStorage",
    "activeTab",
    "https://www.linkedin.com/*",
    "https://easyleadin.com/*"
  ],
  "web_accessible_resources": [
    "assets/*",
    "icons/*"
  ],
  "externally_connectable": {
    "matches": [
      "https://easyleadin.com/*"
    ]
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.linkedin.com/*"
      ],
      "all_frames": false,
      "css": [
        "content-scripts/app.css"
      ],
      "js": [
        "content-scripts/app.js",
        "content-scripts/linkedinFeatures.js"
      ]
    },
    {
      "matches": [
        "https://www.linkedin.com/*"
      ],
      "all_frames": true,
      "js": [
        "content-scripts/navTracker.js"
      ]
    },
    {
      "matches": [
        "https://easyleadin.com/*"
      ],
      "all_frames": false,
      "run_at": "document_end",
      "js": [
        "content-scripts/shareImporter.js",
        "content-scripts/templateImporter.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": {
      "16": "assets/icon-16.png",
      "32": "assets/icon-32.png",
      "48": "assets/icon-48.png",
      "128": "assets/icon-128.png"
    }
  }
}