Mailman brought me 4 of these today, did not order and no return address and no documentation.
My current interest is addressable LED's and they resemble that. So small I had to fire up the digital microscope to capture image.....Any info much appreciated!
That is what they are, and you might find a part number on the side of the case.
Looks like an SK6812 (a near-clone of WS2812) RGBW LED mounted on a little PCB.
Try talking to them like that - the major libraries support.
Looks to me like one of those addressable RGB or RGBW LEDs. Like a WS2812B -- but NOT, because of that semi-circular yellow region that looks like a white LED. The Din and Dout, suggest these are serially addressable, but the yellow region suggests these have a White channel.
Perhaps, these SK6812 breakouts:
https://www.ebay.com/i/263407892116?chn=ps&var=562426404391
