Some organization is required or we wind up with 
dozens of different version of the same library
(usually jquery).

Javascript libraries should be placed in
their own directory. An entry in the CurrentVersions.txt
file should indicate which version of the library
is in that directory. CSS files bundled with the
javascript library belong here even though they
are not javascript per se.

Optionally, place a symlink without version number
in the top level pointing at a particular version
of a library. When these symlinks are provided, pages
should use the symlink URLs to avoid rewrites if
the underlying javascript libraries are upgraded.

Files in the composer-components directory are installed
via PHP's package management tool, composer.