What’s the difference between these two?
(sorry I couldn’t help myself)
There is only one starter theme for WordPress from the Pinegrow Team and you can find it here:
It’s a paid “product”.
I came across this free download of what looks like PG Starter Theme
The HTML sources (including the WordPress actions from Pinegrow) is not included with the Free PGBootstrapStarter WordPress theme. (and child theme)
This theme It’s our way to show what you can build when you use the WordPress Starter Theme but because of the very similar names I understand your confusion