Ask HN: Why does Facebook.com activate the microphone?

In Safari on macOS when visiting the Facebook newsfeed, the system mic active icon appears in the menu bar and says that Safari is using it.

I haven't granted permission. When I asked ChatGPT it said 'Safari creates an audio capture session even if the user has not granted microphone permission, for capability negotiation, but no audio data leaves the device until permission is granted.' - is that accurate?