Challenge 3: A Leftover NameVirtualHost Line on Apache 2.4 —
Solution Walkthrough

Is it a fatal error?

No. Apache 2.4 doesn't refuse to start because of a leftover
NameVirtualHost line -- the server starts normally and continues
serving requests.

Is it still doing anything useful?

No. Per this chapter's own material, Apache 2.4 removed the
requirement that NameVirtualHost be explicitly declared to enable
name-based matching -- any IP:port shared by more than one
VirtualHost automatically becomes name-based now, with no separate
directive needed. Apache logs a deprecation warning to the error log
at startup noting the directive is no longer needed, and then simply
ignores it. The line isn't breaking anything, but it also isn't doing
any real work anymore -- it's dead configuration left over from an
Apache 2.2-era workflow, safe to delete rather than something that
needs to be "fixed" or replaced with a modern equivalent.

WHY THIS WORKS AS AN ANSWER
------------------------------
This exercise checks that the reader can correctly distinguish
"deprecated and ignored with a warning" from "fatal error" -- a real,
practical distinction when working from an older tutorial or
migrating an existing config forward to a newer Apache version.