I'm not sure if this is intended, but I ran into some nice/useful behavior of the spread-dot operator when applying to a list of lists. I was trying to use collectMany and found that I would need to do an inner collectMany or switch to inject. But it turns out spread-dot and flatten handled the situation very nicely.
Could you please add a note on this to the documentation (section 1.2.8 – other operators)? I don't think it is common knowledge that spread-dot does not always gather up results in a flat list.