Three different #ActivityPub spec guides - three different answers!
FEP-7628 says a Move has an ID, To, & CC.
https://codeberg.org/fediverse/fep/src/branch/main/fep/7628/fep-7628.md
SocialDocs says just an ID, no To nor CC.
https://socialdocs.org/docs/guides/account-migration/#the-move-activity
SWICG says no ID, nor To, nor CC.
https://swicg.github.io/activitypub-data-portability/#process-0