Have you checked github ? Check the link - github dot com /unacms/UNA/releases/tag/15.0.0-A1 (I cant pastte link, so change dot to .). under the assets .

github dot com/unacms/UNA/releases/download/15.0.0-A1/UNA-Spacenook-v dot 15 dot 0 dot 0-A1 dot zip

ooff... I cant even paste a zip file name here.. It doesnt allow it ..

So there is a spacenook release for this alpha release... whatever that means.