MoD reader JX324 noted that the KRANA-KAL descriptions have also been added to the official website.

The KRANA-KAL, like the KANOHI NUVA, are all basically just more powerful versions of the originals, except the XA-KAL, which is specifically required to free the BAHRAG.

Also of note is that the official colors have been included: bronze (TK), copper (NK), iron grey (PK), steel blue (GK), metallic green (NK), and pearl (KK). Personally, I think the first three would make more sense if they were copper (TK), iron grey (NK), and bronze (PK).