How set up the "native Tasmota discovery"?

The information is sort of a mess and all over the place and most of the discussions go nowhere. It used to be ‘setoption19 1’ for discovery, but now it’s ‘setoption19 0’ for the new one and ‘setoption19 1’ is the old one or (soon?) turned off. Not sure what they’re planning to do about backwards compatibility, possibly nothing.

Tasmota/CHANGELOG.md at development · arendst/Tasmota · GitHub
Prepare to remove dedicated Home Assistant discovery in favour of Tasmota Discovery and hatasmota

SetOption19 Tasmota discovery protocol used in Home Assistant Tasmota integration
0 = enable Tasmota discovery (default)
1 = use deprecated MQTT discovery (only with #define USE_HOME_ASSISTANT, does not exist in release binaries)

Tasmota devices configured for native discovery (SetOption19 0)

USE_HOME_ASSISTANT has been removed from standard binaries in favor of TASMOTA_DISCOVERY
You are strongly advised to move to the HATASMOTA plug-in as the old way is in way of absolescence

If you absolutely want to use the old and deprecated way you’ll have to compile yourself.

Also there’s some stuff here already that might or might not be related: