I've noticed that many of the audio tour devices they provide in museums and palaces in Europe do not have any earphones. They have a plug for earphones, but they don't provide earphones. They expect you to just hold the device up to your ear like a phone. If you carry a pair of earbuds, you can just plug them in and listen handsfree.
It used to be that many people carried earbuds anyway. But now many people have Airpods or the android equivalent. Those are great, but won't work with audio tour devices. For that you need a pair of old school wired earbuds.