Examine source code of Web MIDI API

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "author": "Jazz-Soft",
  "version": "1.0.2.6",
  "icons": {
    "128": "icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "_JZZ.js",
        "content.js"
      ],
      "all_frames": true,
      "run_at": "document_start"
    }
  ],
  "default_locale": "en",
  "homepage_url": "https://jazz-soft.net"
}