Examine source code of Remove Spaces

{
  "manifest_version": 2,
  "name": "Remove Spaces in Text Field",
  "version": "1.3",
  "description": "Remove spaces between words in a text field using Alt+1",
  "icons": {
    "48": "icon.png"
  },
  "commands": {
    "remove-spaces": {
      "suggested_key": {
        "default": "Alt+1"
      },
      "description": "Remove spaces between words in the active text field"
    }
  },
  "permissions": [
    "activeTab",
    "scripting"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d94fe3fe-aab6-4848-9ecc-1bc1b4fa5d1e}"
    }
  }
}