"ESP32 CSI Toolkit", papers+code, Virginia Commonwealth University, USA https://stevenmhernandez.github.io/ESP32-CSI-Tool/

"Wi-ESP", papers+code, KITS WRL, South Korea, https://wrlab.github.io/Wi-ESP/

"Espressif CSI sample applications", Shanghai, China, https://github.com/espressif/esp-csi

"CSI-MURDER", paper+code, WiFi Sensing countermeasures, EU, https://ans.unibs.it/projects/csi-murder/

I believe that was the initial paper which really started the Wi-Fi sensing research. Although a lot of research has come after that. It's a really fascinating technology with a whole range of possibilities beyond just motion and presence sensing.