Examine source code of CaptionCatch

{
  "manifest_version": 3,
  "name": "CaptionCatch",
  "short_name": "CCatch",
  "version": "5.13.0",
  "description": "Learn Japanese, Chinese, or English vocabulary from subtitles as you watch. Free on YouTube; Pro adds Netflix & more.",
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "permissions": [
    "storage"
  ],
  "host_permissions": [
    "https://*.netflix.com/*",
    "https://*.youtube.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://*.netflix.com/*",
        "https://*.youtube.com/*"
      ],
      "js": [
        "lib/storage-migrations.js",
        "lib/pro-status.js",
        "lib/kuromoji.js",
        "lib/dictionary-engine.js",
        "lib/dictionary-engine-zh.js",
        "lib/dictionary-engine-en.js",
        "content.js"
      ],
      "css": [
        "styles.css"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "lib/kuromoji-dict/*",
        "lib/vocab-bank.json",
        "lib/meanings/*.json",
        "lib/vocab-bank-zh.json",
        "lib/meanings-zh/*.json",
        "lib/jieba/*",
        "lib/vocab-bank-en.json",
        "lib/meanings-en/*.json"
      ],
      "matches": [
        "https://*.netflix.com/*",
        "https://*.youtube.com/*"
      ]
    }
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "CaptionCatch",
    "default_icon": {
      "16": "icon16.png",
      "48": "icon48.png",
      "128": "icon128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "captioncatch@kaouri.dev",
      "strict_min_version": "128.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}