Extra data in APDU response when signing by OpenPGP card

[Ivan Markin]

NIIBE Yutaka:
> It is because of the encoding in gpg-agent/scdaemon.
> 
>   (1) 25 32 35 is: % 2 5
>   (2) 25 20 44 is: % 0 D
> 
> (1) is to escape '%' (ASCII value 0x25).
> (2) is to represent CR (ASCII value 0x0d).

Thanks!
Where I can read more about it? Are these encodings the only ones?

-- 
Ivan Markin