“Since the beginning of this year the fritz.box DNS suffix is an actual registered domain and the owner of this domain is not AVM or anyone affiliated to them.”
Fritz!Box hands out fritz.box as a DNS suffix and won’t let you turn it off. Since January, fritz.box is a registered domain and AVM doesn’t own it. Anyone running Pihole or Adguard sends lookups to that stranger, and Windows appends the suffix to every request. AVM’s answer is a tweet saying the domain is “in the process of being sold.”