echo “” – bug or not?

If you write about echo “”, i.e. outputting empty space, no spaces, and no characters at all, is this considered a bug/exploit/bug?

Answer 1, authority 100%

echo ""; // 
echo; //     

Output: If you write an echo, at least something needs to be output. Even an empty line.
You can also do this:

echo null; //

but what for? ©