What happens to my Apple Music yearly subscription when I switch to Apple One?

Bundle Apple subscriptions with Apple One - https://support.apple.com/HT211659

"If you already subscribe to Apple Music, Apple News+, Apple Arcade, or Apple TV+, you don't need to cancel those subscriptions. They will automatically be canceled when you're billed for Apple One."

Apple One "In case you missed anything." FAQ at the end of this page --> https://www.apple.com/apple-one/

"What happens with my annual payment subscriptions if I move to Apple One?"

July 2021 post by ASC contributor Roger Wilmut1 - https://discussions.apple.com/thread/252924036

"Either the unused part of your existing subscription will be refunded or it will be used to discount the first Apple One subscription."