This is what I can tell you for now. There is a file called \esoui\libraries\globals\globalapi.lua.
The variable names of the cached Lua function references are:
Lua Code:
zo_strlower = LocaleAwareToLower
zo_strupper = LocaleAwareToUpper
string.lowerbybyte = string.lower
string.upperbybyte = string.upper
string.lower = zo_strlower
string.upper = zo_strupper
zo_strsub = string.sub
zo_strgsub = string.gsub
zo_strlen = string.len
zo_strmatch = string.match
zo_strfind = string.find
zo_plainstrfind = PlainStringFind
zo_strsplit = SplitString
zo_loadstring = LoadString
zo_floor = math.floor
zo_ceil = math.ceil
zo_mod = math.fmod
zo_decimalsplit = math.modf
zo_abs = math.abs
zo_max = math.max
zo_min = math.min
zo_sqrt = math.sqrt
zo_randomseed = math.randomseed
zo_random = math.random
If you look closely you will find your function.
