Exercise 2: Seeing Inside a Detached Session — Possible Solution
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Create the session without attaching (Chapters 8 and 9 cover these
options in detail):

  screen -dmS jobs sleep 2000         # detached session, window 0
  screen -S jobs -X screen top        # add window 1 running top

Inspect it:

  $ screen -ls
          61007.jobs      (Detached)

  $ pstree -p -a 61007
  SCREEN,61007 -dmS jobs sleep 2000
    ├─sleep,61008 2000
    └─top,61015

The two children of the SCREEN server are the programs in its two
windows. Because each window was started with a command rather than a
shell, the programs appear directly under SCREEN, with no bash in
between (compare the chapter's example, where each window was a
shell).

(Clean up afterwards with: screen -S jobs -X quit)

WHY THIS WORKS AS AN ANSWER
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It uses the session ID's PID as the root for pstree, which is the key
technique, and explains why the tree shape depends on how each window
was started.