The score starts at 100 and loses points for each problem found, more for serious ones than small ones. The checks cover whether the profile is connected and complete, how many photos it has, whether anything has been posted in the last two weeks, how many services are listed, how often reviews are coming in, what the recent rating is, and whether there's a current offer.
Every item on the list is marked as one the product fixes or one you fix. What it fixes is the wording on your profile. It rewrites the business description each month, adds descriptions for services you've confirmed, and switches on the yes-or-no attributes Google offers that truthfully apply to your business.
It also keeps an eye on what it doesn't change. If your profile has no opening hours, it adds the ones from your setup. If hours already exist, it never overwrites them; when they change on Google, you get a task telling you so.