Using Blog Template Plugin

I have just downloaded the Blog Template plugin suggested in and am reading the instructions, which say "New blogs created through the Site Admin -> Blogs menu will have the template named 'default' applied"

Does this mean the template will be pulled from the theme 'folder' named 'default,' or the theme whose style.css 'Theme Name:' says 'default,' or the one that says 'Wordpress default?'

So many defaults. No one to know.

Oh me, oh my.