[ What does it mean to dump an array? ]
I am unfamiliar with this concept of dumping an array. Does it mean to remove all contents of an array? Also this concept of dumping. What does it imply?
The term "dump" in computing is an old one, going back at least to the 1970's and probably a lot further than that.
Classically, it meant to output the values of something in an uninterpreted form (e.g. octal or hexadecimal) that can then be used when diagnosing a problem. (So for example, I recall reading computer printouts with "register dumps" and "core dumps" to try to figure why my CDC 6400 programs had crashed ... when I was an undergraduate in 1970-something.)
Without seeing the context, it sounds like "array dumping" is the same idea; i.e. output / display the array contents to see what is in it, for diagnostic purposes.