Examine source code of org-protocol

{
  "manifest_version": 2,
  "name": "org-protocol",
  "author": "Wojciech Siewierski",
  "version": "1.3.1",
  "icons": {
    "48": "emacs48.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "org-protocol@einval.eu",
      "strict_min_version": "63.0"
    }
  },
  "page_action": {
    "browser_style": true,
    "default_icon": "emacs48.png",
    "default_title": "org-store",
    "default_popup": "popup/store.html",
    "show_matches": [
      "<all_urls>"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ]
    }
  ],
  "commands": {
    "_execute_page_action": {
      "suggested_key": {
        "default": "Ctrl+Alt+E"
      },
      "description": "Store site with Emacs org-mode"
    }
  }
}