general
-------

- check for user macros starting with \luatex

compat
------

- \EnsureLuaTeXPrimitive
- use it in other packages, and test them with various versions

loader
------

- make a real test using a fake texmf tree as TEXMFHOME?
- anyway, give it some real testing with luatex < 0.43!
- ensure compatibility with older versions of LuaTeX (no 'lua' type for
  kpse.find_file).
- Make a decision about the behaviour (discuss this with Heiko & all)

modutils
--------

Review extensively.
- names starting with \luatex
- logic (see what LaTeX2e does)

mcallbacks
----------

Review extensively.
Incorporate remaining bits from luatextra?