The as_root checkbox help says what it now does

It described the control as a hint whose effect was decided at run time, which was
true and misleading: the paths are chosen here, at render time, and the command
follows.

web/uadmin/nodes.html

@@ -122,10 +122,12 @@
                 Expect to run as root on an exclusive machine
               </label>
               <small class="field-hint">
-                Chooses the expected install layout — <code>/opt/umbra</code> with a system
-                service running as its own account, or the user's own directories with a
-                user service. The script checks for root when it runs and takes whichever
-                branch is actually available, so this is a hint, not a requirement.
+                Ticking this changes the command below to <code>curl … | sudo sh</code> and
+                installs to <code>/opt/umbra</code> with a system service running as its own
+                <code>umbra-node</code> account. Unticked, everything stays in your home
+                directory with a user service. The script still checks for root when it
+                runs, so it does the right thing either way — but the paths it writes to
+                are chosen here, so a mismatch would fail.
               </small>
             </div>