Mount for infrared optical water sensor widely available on ebay and elsewhere ("Infrared Water Liquid Level Sensor Control Switch") . Sold by DFrobot as Sensor-FS-IR02, https://wiki.dfrobot.com/Liquid_Level_Sensor-FS-IR02_SKU__SEN0205. Tutorial presented here, https://www.electroschematics.com/optical-liquid-level-sensor/. Mount slides under container and holds sensor about 6 mm above bottom of tray. In this position, the sensor detects if water is standing in tray or saucer. This is part of an automatic irrigation system - watering is canceled if water is standing in tray. Openscad file included for customization. Rotate model 90 degrees to in pursaslicer to avoid the need for support.
The author hasn't provided the model origin yet.