[e_proxus]

- 'parent' goes to the comment that is replied to

- 'prev' / 'next' goes to the adjacent sibling comments

- 'root' goes to the top level comment in the thread (not the post)

They are very useful on mobile if you're deep in a thread, and want to go to the next top-level thread. To do that, press 'root' and then 'next' (or collapse it with [-]).