New update - and new question about branch

Greetings.
Today my Win10 wanted to restart because of a new windows update, so I let it do that.
Now I have a new setting (??) under advanced options in "Update & recovery".
The last setting are like this:
"Choose what branch you'd like to get new previews builds from."!

Then a selectorbox, but only with one possibillity:
flb_awesome1501

Do I have some dirt in already? Or is this in fact a Microsoft updatesetting??

I think "flb_awesome1501" does not sound like a Microsoft parameter, but I can be wrong?

It is a planned update, not yet available. Microsoft have confessed to an error where the interoffice build was shown accidentally but not available. It was quickly withdrawn.

It is alleged that the new windows (10) will be called awesome.

Just let it ride until the next becomes available.

Okay, thank you very much for that info :).

That saved me a new clean install

It's a beta, so there will be hints of the developers goofing off or being blunt before the marketing and consumer experience people have a chance to erase all of the traces.

No doubt that is the official branch, though internally they probably have an easy way to add other branches to use.