Public API
Setting your account to public is very easy and can be done in seconds, allowing you to join in on certain community events that require stat tracking, track your own progress, or see who might have what you need.
If you're scrambling wondering if yours is set to Public or Private, by default it is Public when you make your account.
How To Set Your Profile's API As Public
Click the Gear Icon in the bottom left.
Click Other links at the bottom.
Click the Checkbox so it becomes Orange.
That's it, you're done and are now free to join community created sites that need access to your Public API.
What It Does
Setting your API to public makes it accessible to the general public or external developers, allowing anyone to consume its data or functionality without needing special permissions or internal network access. Allowing player ran sites to get your stats to display.
Why Does It Matter
Having your profile set to public allows you to join community events hosted on player ran sites. On these sites you can do various things like track your XP, items, kills, minigame progress etc.