Examine source code of View Source Switch

{
  "manifest_version": 2,
  "name": "View Source Switch",
  "description": "One-click switch between web page and view-source",
  "version": "4.0.0",
  "author": "Florent Tassy",
  "homepage_url": "https://gitlab.com/florent_tassy/view-source-switch",
  "browser_specific_settings": {
    "gecko": {
      "id": "view-source-switch@ftassy.github.io"
    }
  },
  "permissions": [
    "tabs",
    "storage",
    "contextMenus"
  ],
  "browser_action": {
    "default_title": "View Source Switch",
    "default_icon": "icons/dark-icon.svg",
    "theme_icons": [
      {
        "light": "icons/dark-icon.svg",
        "dark": "icons/light-icon.svg",
        "size": 16
      },
      {
        "light": "icons/dark-icon.svg",
        "dark": "icons/light-icon.svg",
        "size": 32
      }
    ]
  },
  "icons": {
    "16": "icons/dark-icon.svg",
    "32": "icons/dark-icon.svg"
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "js/content.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+U"
      },
      "description": "Switch web view - source view"
    }
  }
}