To reproduce bug:

  1. yarn install
  2. Copy .env.example to .env and populate if necessary
  3. yarn build
  4. yarn start

Output is

Discord.js client is ready!
--------------------------------------------------
Core Dependencies
- @discordjs/voice: 0.7.2
- prism-media: not found

Opus Libraries
- @discordjs/opus: not found
- opusscript: not found

Encryption Libraries
- sodium: not found
- libsodium-wrappers: not found
- tweetnacl: not found

FFmpeg
- version: 4.4
- libopus: yes
--------------------------------------------------

even though

{
  "dependencies": {
    "@discordjs/opus": "^0.6.0",
  }
}