Red X by tags in playground

Question

When I am practicing code in the playground, after I create a head or body as taught. it displays a red X on the left of the tag or row in general. Why is that?.. Because when I run it, the output looks as expected?...

Answer 1

What does the tooltip say when you hover the mouse over it?

Answer 2

"Unexpected end tag (ignored)" Im just a little confused as to why it displays a red x although it will be ignored..? or is it?.. Not sure if im doing something wrong or if the system found something that was corrected (hence the ignored in parentheses).