This sentence "bytes with a numeric value of 128 or greater must be expressed with escapes" is wrong and not complete. The value needs to be escaped is >= 127 and < 32.

While they probably should be entered with escapes, there's no actual technical requirement for that.

From the command line, I can enter a control-A with control-V control-A (this might be different depending on your environment, or if you use an editor). This will enter a literal string containing a single character with value 1.

That gives:

>>> '^A'     # ^A is the combination control-V control-A
'\x01'
>>> len('^A')
1
>>> ord('^A')
1
>>> b'^A'
b'\x01'

Ooh, sorry. It seems I misunderstand the meaning of the sentence. I understand the value as the output of repr, I mean b'\x01'. It means how it's created.

Thanks for your reply and sorry for the noise. I close this then.

No problem! Thanks for caring enough to open an issue and submit a patch, even if we don't use it.