How to remove this Mavic spoke cover from the rear wheel?
I've not worked on this kind of wheel before, but it looks like the ball-end of the spoke is retained in a recess in the hub, and there's a big C clip stopping them from moving sideways (or up as in this photo)

Option 1: Use a pair of circlip pliers in the Green gap, to spread Yellow circlip apart and ease them over the Red fixed plate.   Do be careful because they may sproing into your face - there's a lot of energy in these.  You might do it with other tools but is even less safe.
Option 2: the red ring may be threaded on, and it may need a simple chain whip to remove.  If so, it may be left or right-hand threaded, and the circlip will just fall off easily exposing the ball joint for your spokes.

According to   https://tech.mavic.com/tech-mavic/technical_manual/data/docs/themes/2_12.pdf  page 7, this info is available in &quot;2003 TM page 23&quot;  from www.tech-mavic.com but that requires credentials to log in.
Mavic's public information only spans the last 5 years.
You might find more infomation by checking each wheel at    https://tech.mavic.com/tech-mavic/technical_manual/data/mavic_tech.php?family=1010   and look for a match.