Examine source code of SF HotSwapper

{
  "name": "SF HotSwapper",
  "version": "1.3.1.22",
  "manifest_version": 2,
  "icons": {
    "16": "assets/hotswapper_16.png",
    "48": "assets/hotswapper_48.png",
    "128": "assets/hotswapper_128.png",
    "1024": "assets/hotswapper_1024.png"
  },
  "description": "Better Salesforce license management and higher safety by automatically (de-)activating users",
  "permissions": [
    "storage",
    "cookies",
    "https://*.salesforce.com/*",
    "https://*.force.com/*",
    "https://*.site.com/*",
    "https://*.salesforce-experience.com/*",
    "https://*.salesforce-sites.com/*",
    "https://*.salesforce-hub.com/*",
    "https://*.salesforce-communities.com/*",
    "https://*.documentforce.com/*",
    "https://*.forceusercontent.com/*",
    "https://*.lightning.com/*",
    "https://*.hotswapper.net/*",
    "https://hotswapper.net/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://*.salesforce.com/*",
        "https://*.force.com/*",
        "https://*.site.com/*",
        "https://*.salesforce-experience.com/*",
        "https://*.salesforce-sites.com/*",
        "https://*.salesforce-hub.com/*",
        "https://*.salesforce-communities.com/*",
        "https://*.documentforce.com/*",
        "https://*.forceusercontent.com/*",
        "https://*.lightning.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "sfhotswapper@repattern.de"
    }
  }
}