Isn't Mumble open source?

Raw JSON

{
  "kind": 1,
  "id": "d6fc6802dd3acb9910a938e190a8356a71d31f7b5005d0ee31d06a20312ecb86",
  "pubkey": "4b77772d68c6143499882f70153fc53aef8d27da5e45ac5525d7d349009c363e",
  "created_at": 1772844662,
  "tags": [
    [
      "p",
      "fd5989ddfadd9e2af6ceb8b63942a9e31b37367e89917931ede3b2ea76823f10",
      "wss://nostr.1sat.org/"
    ],
    [
      "p",
      "552ba911d5905344a39b89c029bc8620056b73aebe4a894ec1e7dc85f5be71d0",
      "wss://nos.lol/"
    ],
    [
      "p",
      "552ba911d5905344a39b89c029bc8620056b73aebe4a894ec1e7dc85f5be71d0"
    ],
    [
      "p",
      "fd5989ddfadd9e2af6ceb8b63942a9e31b37367e89917931ede3b2ea76823f10",
      "wss://nostr21.com/"
    ],
    [
      "e",
      "91fcc437607ca7985d601ddf48d44162caf646b452616762a78ab0fbf2837615",
      "",
      "reply",
      "552ba911d5905344a39b89c029bc8620056b73aebe4a894ec1e7dc85f5be71d0"
    ],
    [
      "e",
      "abb2b19ea11c8979f835e431009ec5ae0b2242ec3cde60594b9415478ef73cc7",
      "wss://relay.primal.net",
      "root",
      "fd5989ddfadd9e2af6ceb8b63942a9e31b37367e89917931ede3b2ea76823f10"
    ]
  ],
  "content": "Isn't Mumble open source? \n\n",
  "sig": "dd867409dd9871b2d244385e9ab18f9ce19263b0022f78ec5c31156b99a44e8fd65d77e28a20b72476ca9fe6796b0bf92c4107d9976d058336cf893b56329e7c"
}