MLLP.Envelope.sb
You're seeing just the function
sb, go back to MLLP.Envelope module for more information.
The MLLP Start-Block character. In documentation it is often represented as <SB>.
The sb is a single-byte character with the ASCII value 0x0B. This character is
also know as "VT (Vertical Tab)" and may appear as \\v or ^K in text editors.
Examples
iex> MLLP.Envelope.sb
" "