The jurisdictional status of .local and other standards-reserved special use domains is explained by RFC 6761 section 3:

https://datatracker.ietf.org/doc/html/rfc6761#section-3

And ICANN is bound by the IETF/ICANN Memorandum of Understanding Concerning the Technical Work of the IANA, which prevents it from usurping that jurisdiction:

https://www.icann.org/resources/pages/agreements-en