It’s such a shitty situation. ICANN is not going to sell .home or .corp as they found a crapton of traffic when they checked for it, but IETF never finished an RFC for them - however people easily stumble into the draft RFC that lists what they were thinking of, and assume stuff like .lan is good to go too. They’re safe by ICANN policy, but unsanctioned.
.home.arpa is safe, per RFC, but user unfriendly to normal people. There are a few others but none a corporation would realistically use. I’ve used . internal for lab testing stuff for ages, so this is extra good news for me I guess.
Really I wish they’d have just reserved the most common ones rather than getting caught in some bureaucratic black hole.