Why isn't monitorLibrary in usage?

Using latest nightly, the help usage is:

Usage:
    kiwix-serve [OPTIONS] ZIM_PATH+
    kiwix-serve --library [OPTIONS] LIBRARY_PATH

Purpose:
    Deliver ZIM file articles via HTTP

Mandatory arguments:
    LIBRARY_PATH        is the XML library file path listing ZIM file to serve. To be used only with the --library argument.
    ZIM_PATH        is the path of a ZIM file.

Optional arguments:
    -a, --attachToProcess   exit if given process id is not running anymore
    -d, --daemon        detach the HTTP server daemon from the main process
    -i, --address       listen only on this ip address, all available ones otherwise
    -m, --nolibrarybutton   do not print the builtin home button in the builtin top bar overlay
    -n, --nosearchbar   do not print the builtin bar overlay on the top of each served page
    -b, --blockexternal prevent users from directly accessing external links
    -p, --port      TCP port on which to listen to HTTP requests (default: 80)
    -r, --urlRootLocation   URL prefix on which the content should be made available (default: /)
    -t, --threads       number of threads to run in parallel (default: 4)
    -v, --verbose       print debug log to STDOUT
    -V, --version       print software version
    -z, --nodatealiases create URL aliases for each content by removing the date
    -c, --customIndex   add path to custom index.html for welcome page

Documentation:
    Source code     https://github.com/kiwix/kiwix-tools
    More info       https://wiki.kiwix.org/wiki/Kiwix-serve

There is no mention of the fantastic monitorLibrary option which does work with this version. Is that on purpose?

kiwix / kiwix-tools

Why isn't monitorLibrary in usage? #510