It never made sense. The original hash bucketing mechanism for the function lookup in PHP was the length of the name of the function, so each new function was named a specific length to ensure the function list was evenly distributed across the hash table.
Well, there were other factors in play there. htmlspecialchars was a
very early function. Back when PHP had less than 100 functions and the
function hashing mechanism was strlen(). In order to get a nice hash
distribution of function names across the various function name lengths
names were picked specifically to make them fit into a specific length
bucket. This was circa late 1994 when PHP was a tool just for my own
personal use and I wasn't too worried about not being able to remember
the few function names.
