I’ve seen it often in your shop and elsewhere. A device is called Arduino compatible in the description.
But what does it really mean?
In the beginning there was only the 5V Arduino family, but lately there are 3.3V only or 3,3V with some 5V tolerant GPIO pins boards available.
Pretty easy to confuse these things and grill a controller with a 5V sensor-signal or get frustrated, because the compatible sensor doesn’t work with 3,3V.
Isn’t it time to change that description to something more accurate?
Normally “Arduino Compatible” these days refers to compatibility with the Arduino IDE / software and how it’s programmed. The pinout, voltage and shield compatibility have fallen a bit to the wayside in terms of descriptors, though manufacturers still tend to mention “shield compatible”.