First I must say, I am very happy that it is communicated, that is very welcome. It is however not pleasant for the volunteers who have to work with it are given the impression that if it is not under WMF, that somehow it is less important or something...
Please realize, WMF is maintaining the infrastructure not for itself but for the whole Wikimedia movement. For historical and some practical reasons, some parts are maintained/organized by chapters who do that to support the volunteers who all strive to improve the content of the projects. Please try to act like this matter is divided over two separate departments who need to work together here, if that is kept in mind it gives a much better impression and works better I think.
I do not think that it matters if there was given a guarantee or not, that is not the point. The fact that we could use these addresses is because it was set up this way, absolutely not a happy accident. There is also a very good reason to use these e-mail addresses, they look more trustworthy for the public to use.
For me this stuff is totally unknown. I have no idea what is meant. What I do know is that we would like to keep using these addresses for sending and receiving e-mails through the OTRS system.
If I am not mistaken, Siebrand is the person who has set this up or is maintaining it. I do not think he is on this mailinglist.