Most of the bundling w.r.t. to native dependencies can be
disabled where Debian packages are already available (with
configure flags --without-embedded-sqlite3 --without-embedded-lua --without-embedded-lmdb
). Is this tested? No. I guess tclap could be handled
similarily... but that one would only be a build dependency. There
are also native dependencies that aren't packaged in debian yet
like miniz ( https://github.com/richgel999/miniz ) or libfastcgi.
On the web UI front it has a lot more dependencies and some are
in debian (like bootstrap, datatables, jquery). The API there is a
lot less stable there so unbundling would be harder there.