Proper shebang for python3

[Manfred Lotz]

Hi there,
Pretty new to python I've got a question regarding the proper shebang
for Python 3.

I use 
   #!/usr/bin/python3

which works fine.

Today I saw 
   #!/usr/bin/python3 -tt

and was wondering what -tt means.

Being on Fedora 30, Python 3.7.3 the man page of python3 doesn't even
mention -t. 

python 2 man page mentions

       -t     Issue a warning when a source file mixes tabs and spaces
       for indentation in a way that makes  it  depend  on  the worth
       of a tab expressed in spaces.  Issue an error when the option is
       given twice.

I guess that -t has the same meaning with python 3.7.3. 


My questions:

1. Is my guess correct?

2. Is it a bug that it is not mentioned? python3 --help doesn't mention
it either.


-- 
Manfred