In the dashboard, each theme will have two files:

• theme-name-installable.zip (Main installable .zip file)
• theme-name-extras.zip

theme-name-installable.zip is installable theme zip which is meant to be uploaded directly in the WordPress to install the theme (sample docs for Adrenaline).

In the extras .zip theme-name-extras.zip you will find all other files like information about the license, the child theme, and usually some other assets (some images for background etc.). You can unzip it to see what’s inside. This .zip it’s not meant to be installed directly in the WordPress.