Examine source code of Toggle .h <-> .cpp

{
  "manifest_version": 2,
  "name": "Toggle .h <-> .cpp",
  "description": "Toggle between a url which ends in .h and a url which ends in .cpp",
  "version": "1.0.2resigned1",
  "icons": {
    "128": "icon.png"
  },
  "permissions": [
    "<all_urls>",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "commands": {
    "toggle-h-to-cpp": {
      "suggested_key": {
        "default": "Alt+C"
      },
      "description": "Toggle between a url which ends in .h and a url which ends in .cpp"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4b0c7efc-c6fb-42ed-9d0c-bdc8f43f1662}"
    }
  }
}