An Apple TV tried to AirDrop me a system diagnosis archive. What happened?

The Apple TV supports creating sysdiagnose bundles and sending them over AirDrop. Apple staff recommend this regularly on the Apple Developer Forums.

To capture a sysdiagnose, hold down the Play/Pause and - buttons on the Apple TV Remote for six seconds, until you see a dialog confirmation on-screen. From there, follow the instructions to AirDrop the sysdiagnose off the device.

^{Beta 7 crashes on HDMI hotplug - Apple Developer Forums}

It's possible something's accidentally held down the buttons on the Apple TV remote (since they are next to each other) which has caused this action.

AirDrop must be a fairly new feature for the sysdiagnose functionality since the guide for creating a sysdiagnose from an Apple TV on the Apple Developer site still says a USB-A to USB-C cable and iTunes are required: Apple TV sysdiagnose Logging Instructions (link behind developer login).