[htrp]

Looks like they used an apple airtag, but couldn't specifically call it that for some reason....

>One shoe of each pair was implanted with a thin, round Bluetooth tracking device.

> a small location tracker was beeping from the back of a crumbling second-hand shoe store. A Reuters reporter followed the high-pitched ping to a mound of old sneakers and began digging through the pile.

[kailanb]

It’s called out later in the article.