Link-local addresses () are assigned automatically on every interface. Routers won't forward them beyond the local link. You use them for neighbor discovery, router advertisements, and next-hop addressing. Even if an interface has no global address, it has a link-local. The format is plus a -bit interface identifier, often derived from the MAC address.
##### ###### ##### ### # # ### # # ###### ## ## ## ## ## ## ## # # # # # ## ##### #### ##### # # # # # # # #### ## # ## ## ## ## # # # # # ## ## # ###### ## ### # ### # ######
$ curl repovive.com/roadmaps/network-design/ip-addressing-and-subnetting/ipv6-link-local-addresses
░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░██████████████████████████████████████████████████████████████████████████████████████████████████