Thanks to the help from this amazing guy at Reddit, I have got an answer for the question:
Usually when you prepare a route for a first ascent you clean it, if
it gets a decent amount of traffic then no further cleaning should be
needed later on. But on alpine routes, long multi-pitches or big walls
you should always be careful of loose rock: too many meters to clean
for a first ascent party, and weathering produces new loose rock every
season. Water gets into cracks, freezes in winter and expands, and
boom, another piece of rock that just waits for you to rip it out or
fall on your head.
So, who are these people who clean the walls for the climbers called?
Or is it just the only one instance where a person actually cleaned a
wall for the climber?
This is probably a rare occurrence where Cedar Wright put more
attention into it because Alex Honnold was about to free solo the
route. If you're on a rope then loose rock sucks and you might fall
because of it, but then the rope catches you.
When you're free soloing you really dont want to grab any loose rock
because falling means you'll very likely die or be physically
What are the equipment used by these people?
It's been a while since i watched that video, but generally to get
around big walls you use fixed static lines and ascenders to get