Complex sentence: Most of the signatures end with the short integer 0x4b50 (read as a little-endian number) which when viewed as an ASCII string the hexadecimal 50 4B read "PK" the initials of the inventor Phil Katz.
Split into simpler sentences: Most of the signatures end with the short integer 0x4b50, which is stored in little-endian ordering. Viewed as an ASCII string this reads "PK", the initials of the inventor Phil Katz.