Examine source code of Passman

{
  "manifest_version": 3,
  "name": "__MSG_extName__",
  "description": "__MSG_extDescription__",
  "version": "3.0.1",
  "icons": {
    "1024": "icon-1024x1024.png"
  },
  "host_permissions": [
    "https://*/*",
    "<all_urls>"
  ],
  "default_locale": "en",
  "permissions": [
    "contextMenus",
    "storage",
    "tabs",
    "scripting"
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "assets/content_styles/*.css",
        "assets/content_styles/*.scss"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ]
    },
    {
      "resources": [
        "content-scripts/content.css"
      ],
      "use_dynamic_url": true,
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ed412846-94d6-4a82-88bd-58b83e43f06d}"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_title": "Passman Webextension",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "open_in_tab": true,
    "page": "options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-scripts/content.js"
      ]
    }
  ]
}