/usr/share/doc/emacsen-common/debian-emacs-policy.gz section "8) Emacs
lisp load path" asks elisp add-ons to add directories with
`debian-pkg-add-load-path-item' rather than directly modifying
`load-path' the way 50elscreen.el does.

I believe debian-pkg-add-load-path-item is available as of "sarge"
emacsen-common 1.4.14 of June 2002.  It keeps /usr/local ahead of
packaged lisp dirs so that anything the sysadmin puts in /usr/local has
precedence.

I notice too 50elscreen.el uses

    (symbol-name flavor)

to make the path.  I think `flavor' is only a dynamic binding from the
site-start.d running code whereas `debian-emacs-flavor' is the
documented variable.  Switching to that might be desirable.