Combing row returning functions using "ROWS FROM"?

I just noticed the reference to combining set returning functions using “ROWS FROM” at https://www.postgresql.org/docs/10/static/queries-table-expressions.html#queries-tablefunctions <https://www.postgresql.org/docs/10/static/queries-table-expressions.html#queries-tablefunctions>

I have not previously noticed this feature, nor seen it used anywhere. The explanation is… terse, and the examples are… missing, AFAICT.

I would love to find a good write-up on how to use this feature. Failing that, I’ll happily write one and post it, if someone here can give me some examples and explanation of the intended use.

I’ll note in passing that this is not a syntax fragment that is very searchable, so please don’t RTFM me… :-)