You don't have to rely on rumors or buried code to know that Apple is working on a tracking tag -- the company has inadvertently spoiled its plans. Appleosophy spotted an Apple support video (unsurprisingly removed) that hints at offline Find My support for currently unannounced "AirTags." The clip didn't provide a peek at the tag or otherwise outline their functionality, although it's clear they'll use Bluetooth to reveal the whereabouts of your lost items. They're believed to use ultra wideband for extra precision.
It's still not certain when the AirTag will arrive (assuming there's no change of plans). However, there have been persistent rumors of new budget iPhones launching in the near future. If that happens, it might make sense to unveil the tag at the same time. Not that there will be much of a rush during the pandemic -- you probably don't need a tracker when you're not even supposed to leave home.