Examine source code of ShowPassword

{
  "manifest_version": 2,
  "name": "ShowPassword",
  "version": "1.0.0",
  "description": "A browser extension that reveals password inputs when the cursor hovers over fields with the `password` type",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "icons": {
    "48": "/icons/icon-48.png",
    "72": "/icons/icon-72.png",
    "96": "/icons/icon-96.png",
    "128": "/icons/icon-128.png",
    "144": "/icons/icon-144.png",
    "192": "/icons/icon-192.png",
    "512": "/icons/icon-512.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "/main.js"
      ]
    }
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "512": "/icons/icon-512.png"
    },
    "default_title": "ShowPassword",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{668b2d00-09c6-450e-809a-f0a6ce6868c7}"
    }
  }
}