Cloudflare also confirmed it:

https://twitter.com/jgrahamc/status/1445068309288951820

Also, the Domain name is for sale???

https://whois.domaintools.com/facebook.com

Weird banner at the top, seems like false advertising as it says a couple lines down: Expires on 2030-03-29

I suspect it's an automated system triggered by DNS not resolving, and they try to "make an offer" if you follow through.

You're right, it's misleading, thanks. Other sites (dreamhost, godaddy) don't list it as for sale.