Examine source code of WaniKani Autocomplete

{
  "manifest_version": 2,
  "name": "WaniKani Autocomplete",
  "version": "1.9",
  "description": "Adds autocomplete functionality to WaniKani.",
  "permissions": [
    "storage",
    "https://www.wanikani.com/*",
    "https://api.wanikani.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.wanikani.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "tooltip.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "wanikani-autocomplete@frederiknorlyk.dev"
    }
  }
}