Vcc - 3.3V
TX - RX
RX - TX
GND - GND
GPIO0 - GND
This device is available on Amazon as "Smart WiFi Plug Outlet Mini with Energy Monitoring." The product number, WK30 appears nowhere on the page on Amazon, so here's its ASIN: B07C326VKR
It remains to be seen if this device actually features energy monitoring as in the title on Amazon.
Nicely labeled holes for a header exist. The pictures below are with a header soldered on. All that was needed was to jumper GPIO0 to ground in addition to the usual connections. Once tasmota is up, configure the device as generic.
This has the LEDs, GPIO4 and GPIO5 separated out as different relays so they can be controlled independently of the switch.