WiFi Health records your WiFi status (Transmit Rate, Signal Strength, Noise Level and SSID) every few seconds and saves it in a local file on your Mac. The data is not sent to Lumination Technologies, nor is it shared with any third party.
Lumination Technologies may receive information about app purchases (and possibly crashes) from Apple, but this is not information that the WiFi Health app has recorded nor controls.
Any questions about this policy may be addressed to LuminationTechnologies@gmail.com