Examine source code of Enhances PubMed

{
  "manifest_version": 2,
  "name": "PubMed Tools",
  "version": "1.0",
  "description": "Enhances PubMed with quick citation copying, PDF links, and metadata extraction tools.",
  "icons": {
    "48": "icons/icon48.png"
  },
  "permissions": [
    "activeTab",
    "https://pubmed.ncbi.nlm.nih.gov/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://pubmed.ncbi.nlm.nih.gov/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icons/icon48.png",
    "default_title": "PubMed Tools"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{970dd2f9-0fa3-4e76-8472-7818830261cc}"
    }
  }
}