Just done a fresh install of website interface on 3.10.0. Run this SQL:

SELECT * FROM ezcontentclass_attribute e where version=1;

You will see that there are drafts of content class attributes. This shouldn't happen of course on a fresh install.

4.0.0alpha1 also seems to be affected, but there are less draft attributes.

Probably related to this, is that the "Template look" class doesn't show up in the "Setup" class group ( class/classlist/4 ) on 3.10.0.