We're barred from being able to use the last character Y/A shows we have (in asking Qs) as it's a reserved...?

Question

We're barred from being able to use the last character Y/A shows we have (in asking Qs) as it's a reserved...?

Answer 1

You have 110 characters to type, according to Y/A, in the first section.  It's actually only 109, though, because the last character is reserved for a ?

Answer 2

...what character is that...so i know not to use it too...

...thanks for sharing...