that's mostly because Knytt XH wasn't made by Nifflas... I can look though if I can find a link and maybe add it too.
Edit by Paula after some consideration: There won't be a link to the XH edition in the board description, because it's a 3rd party mod. For everyone who does not like reading a topic in whole before asking (yes, apparently such people DO exist), here is the link (http://nifflas.ni2.se/index.php?main=03Knytt&sub=043rd_Party_Mods), respectively here the direct one (http://www.ni2.se/files/games/hempuli_knyttxh.zip).