Examine source code of High Contrast Toggle

{
  "manifest_version": 2,
  "name": "High Contrast Toggle",
  "description": "A quick toggle button for browser high contrast mode",
  "developer": {
    "name": "Eitan Isaacson",
    "url": "https://blog.monotonous.org"
  },
  "version": "0.0.4",
  "icons": {
    "64": "icons/icon.svg"
  },
  "permissions": [
    "browserSettings",
    "<all_urls>",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background_script.js"
    ]
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Alt+Shift+C"
      },
      "description": "High Contrast Toggle"
    }
  },
  "browser_action": {
    "default_icon": "icons/icon.svg",
    "default_title": "High Contrast Toggle",
    "theme_icons": [
      {
        "light": "icons/icon_dark.svg",
        "dark": "icons/icon.svg",
        "size": 16
      },
      {
        "light": "icons/icon_dark.svg",
        "dark": "icons/icon.svg",
        "size": 32
      }
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{52ccd3f1-bea0-45e4-a6af-2d28bdc72b0d}"
    }
  }
}