The front rubberized section separates from the back section. I used a knife to push the gap open, then used a credit card and a lot of wiggling. There does not appear to be any glue holding these together, just a tight press-fit.

All of the interesting stuff is in the lower (rubberized) half. This appears to be constructed of several separate pieces, but they are glued together. Attempting to pry off the internal cap just broke it.

Likewise, prying on the outer shell just caused it to crack.

If you look down the barrel from the back, you can see the electronics held in place by the internal cap.

If you cut through the cap at the right place, you can remove the section that holds the electronics in:

Finally, you can use tweezers to pull the electronics out!

All of the electronics are on this one board.

This video has a good discussion of how the Wacom technology works: https://www.youtube.com/watch?v=j4AKwJERxOw

Here's an x-ray of the internals. Posted about here: https://www.reddit.com/r/RemarkableTablet/comments/iozka0/for_fun_an_xray_of_the_remarkable_pen/?context=3