If you are worried about what Facebook apps can see about you then you can limit it.
How to limit/revoke access:-
Step 1 – In Facebook on desktop, click the drop-down menu, then Settings. On mobile, hit the three horizontal line icon at the bottom then Account Settings.
Step 2 – Click Apps and then ‘Logged in with Facebook’ to view all the apps that have access to your data via Facebook.
Step 3 – Select the pencil on desktop, or the arrow on mobile, to view the exact data you’re sharing with each app.
Step 4 – Click the blue ticks to deselect your personal information.
Step 5 – To revoke access completely, click the cross next to the app.