Recently I contributed support for the RuuviTag to Theengs Decoder, an efficient, portable and lightweight C++ library for BLE payload decoding. The RuuviTag RAWv1 and RAWv2 decoders have been added in Theengs Decoder v0.1.7.
As Theengs Decoder is now used in OpenMQTTGateway, a gateway for various wireless protocols that you can install on an ESP32 or other devices, this means that OpenMQTTGateway v0.9.10 also detects RuuviTag advertisements.
And because Home Assistant discovery is enabled by default in OpenMQTTGateway, your RuuviTags are automatically detected in Home Assistant if you have added the MQTT integration.
Read more about it with some examples of the MQTT JSON payload and screenshots on my blog: