Translations:Extension:Scribunto/Lua reference manual/2649/en

An additional local variable named $1 is implicitly declared, and initialized as a standard (and mutable) Lua table containing all arguments values, where the integer position of each argument value given and computed in the function call is the key used to index that value stored in the local $3 table (nil values passed as arguments are not stored in that table, their integer position is just advanced to the next position, so the table is not necessarily a sequence).