Examine source code of Mastodon4 Redirect

{
  "manifest_version": 2,
  "name": "Mastodon4 Redirect",
  "version": "1.4",
  "description": "Redirects users from Mastodon4 supported instances to their home instance",
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  },
  "browser_action": {
    "default_popup": "src/popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "src/m4redirect.js"
      ]
    }
  ],
  "options_ui": {
    "page": "src/options.html"
  },
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "src/background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "mastodon4-redirect@raikas.dev"
    }
  }
}