That's probably just a mistake. Calling split in scalar context will assign the number of items produced by the split to the scalar, so $kbin will contain the number of items the split returns, not the items themselves. That might make sense in some cases, but not here, since $kbin is being used as if it's an array later.

My first guess would be that this was written by a PHP programmer, since their arrays don't use a different sigil like Perl's do.