@markx I don't understand the question

@dominicm Oh I was just asking about what set inccommand=nosplit does

@markx Gives a preview of substitution in real-time

here's the horses mouth: https://github.com/neovim/neovim/pull/5561

This explains it perfectly: https://asciinema.org/a/92207

That is awesome, thanks for bringing it to my attention :)