Odds are your realtor just negotiated those details for you. It is pretty standard everywhere. Very few people want to move those heavy things, so realtors just put them into the contract, if you don't pay attention (you should!) you may not even realize this happened.

When I bought my home, I know that was mentioned explicitly.

Though my understanding is the sale automatically includes all fixtures unless specifically excluded, and I suppose there's a little disconnect there: most major appliances are technically not fixed, but I think most people think of them like they are.

When I sell my home, I was thinking I'd definitely need to put a note on my washer/dryer and smart thermostat, saying I was going to take them with me and they weren't included.