FHT is a range of devices produced by busware.de which allows to interact with various protocols and devices over radio frequencies. It's also possible to build one on your own.
FHT is not produced by busware.de and is not the topic of the Build your own link. It should be CUL, not FHT. CUL is a transceiver for communication with FHT (among other protocols).
https://www.openhab.org/addons/bindings/fht1/ :
FHT is not produced by busware.de and is not the topic of the Build your own link. It should be CUL, not FHT. CUL is a transceiver for communication with FHT (among other protocols).
We may copy the intro text of FS20 binding: https://www.openhab.org/addons/bindings/fs201/