PS:

Peter Münster wrote:
> Would KPSE find texmfcnf.lua in $HOME/texmf/web2c ?
> >From one of your previous messages, I understand that it would *not* find
> it.
>

It does - I messed up the "web2c" string search in the luatex binary;
there are two strings. The right one seems to be:

~/texmf/web2c:/etc/texmf/web2c:/var/lib/texmf/web2c:{~/texmf,!!/etc/texmf,!!/var/lib/texmf,!!/usr/lib/texmf,!!/usr/local/share/texmf,!!/usr/share/texmf}/web2c