Examine source code of Kanji Lookup

{
  "manifest_version": 3,
  "name": "Kanji Lookup",
  "version": "1.0.0.0",
  "description": "Adds more dictionary options to Kanji Koohii",
  "author": "eiernase@kueheaufdsl.de",
  "browser_specific_settings": {
    "gecko": {
      "id": "kanjilookup@kueheaufdsl.de"
    }
  },
  "action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "js": [
        "/scripts/content.js"
      ],
      "matches": [
        "*://kanji.koohii.com/study/kanji/*"
      ]
    }
  ]
}