iOS version: https://apps.apple.com/us/app/nearby-glasses-original/id6761056896

I see some others in the iOS app store that claim to detect nearby “smart” glasses via BLE. I have not tested any of them, so I have no opinion on their usefulness, reliability, privacy, etc:

Nearby Glasses (same name, different app): https://apps.apple.com/us/app/nearby-glasses/id6776279207
Nearby Lens: Glasses Detector: https://apps.apple.com/us/app/nearby-lens-glasses-detector/id6760046620
NoGlasshole: Glasses Detector: https://apps.apple.com/us/app/noglasshole-glasses-detector/id6760988897
Nearby Glasses Ray-Ban Scanner (in-app subscription required): https://apps.apple.com/us/app/nearby-glasses-ray-ban-scanner/id6760216782

Leading to my favorite conspiracy theory, that his shirt choice is really a subtle viral marketing campaign. I call this theory “Tom Scott is in the pocket of Big Red Shirt”.