On Sat, 14 Jan 2017, Daniel Shahaf wrote:

> «${~@}» happens to be a transformation that takes a "$@", interprets
> every word in it as a glob, and returns a list of words.  (Without the
> round parentheses, it'd return something else.)

Although strictly accurate, that's making it seem more mysterious than
it is.  It still returns the same glob results, and in the absence of
the assignment it would be the same list of words, but in an assignment
without the parentheses it would create a string by joining the words
together.