Fair point, I assumed OP meant people of indeterminate identity. Jan Kowalski is indeed the goto placeholder name.

In Poland typically, both officially and informally, one says N. N. (Latin nomen nescio, identity unknown).

It’s an international agreement as per https://www.cloudflare.com/learning/dns/top-level-domain/

Log out and in again, I believe it’s a known issue after upgrade.

Ryanair no longer overbooks flights and in my experience just assigns you random seats (next to each other if you booked multiple tickets). If in doubt just contact their customer support.