AlwaysFlyStar

My friend is flying TXL-LIN and booked the ticket through Air Berlin. However, the plane he got on is an Alitalia plane. Nothing on his booking says anything about Alitalia. And even on Alitalia's website, it says this flight is operated by Air Berlin. Are they sharing planes? Is this a wet lease or something? Or is it just a typical codeshare that my friend (and I) have missed. It is AB 8738. And it's quite surprising to me. Will he be able to collect Avios on this flight?
Apologies if this is a basic question, but I couldn't find any info, and while I have flown many codeshares, the booking tends to indicate the operating carrier somewhere. He even checked in on the Air Berlin app for an Air Berlin mobile boarding pass. I mean, it isn't upsetting or anything, just not something I have encountered before and I thought that somebody here would know what it is. Thanks so much :-)

EuropeToAsia

​​​​​​​Your friend will receive the usual airberlin Avios. It's kind of a wet lease that now seems to happen regularly on Germany-Italy routes. And yes nobody tells you about it, so it seems to confuse many. Sadly for the crews, I fear we might not have either airline by next year.

waffle

And indeed a few others. Air Berlin's TXL–GOT service from the gate next door was operated by Alitalia when I boarded my TXL–FCO flight the other day.

That's true. It's definitely not in the booking confirmation, nor on the boarding pass. I found out about it when I checked ExpertFlyer the day before, but I guess most people didn't know until they saw the plane. That made me wonder about the legality: don't airlines have to tell passengers who is going to operate the flight when they book the ticket?