Binary Code? with a dot? #2

Hi,
and many thanks for this repository.
I have a question regarding binary code provided with the examples, like this one https://github.com/ahmedfgad/ArithmeticEncodingPython?tab=readme-ov-file#example
why does binary code is like 0.0010110?
why there is a dot?
You know, i would like to mare a comparison with Huffman encoding, calculating the length in bits of the messages, but the presence of the . is confusing me.
thanks