Does anyone have any examples using “List of things:join with ...”.
The manual explanation is rather short.
It concatenates a list of string with a separator in between each string:
if the list is ["hello", "world"] and you set $$ as separator you get hello$$world.
You can easily try this operator with a text element and see the result.
It is super useful for generating JSON arrays.
On a more mundane level, listing out tags or categories with commas.