Bil

there isn't really something like "most compatible" with LPPL.

LPPL attempts to preserve the fact that something like LaTeX is a language
which is used for communication, that is if you write a LaTeX document you
expect to be able to send it to me and to work at my end like it does at
yours. This is like when people writing a program in C or whatever they
expect it to compile with the same meaning (as far as statements of the
language are concerned) in different places.

While with most languages it is a reasonable assumption that thier compilers
work in the same way in different places (within limits, I know how much
you have to adjust :-)) the situation with LaTeX as a language is worse:
nearly every package defacto extends the language and so arbitrary changes
to packages will severely limit the use of that language for exchange.

So what LPPL does in a nutshell is to say, ok this piece of software is free
for you do use/modify etc but if you modify you have to ensure that it will
be clear to the users that they are using a variation of the original (in
case of packages the suggestion is, use a different package name, then
things can coexist, though since LPPL 1.3 this isn't a requirement) ---
this is a more formalized (and nowadays perhaps more flexible version) of
Don Knuth original approach with TeX: do what you like with the program and
its algorithms but if you modify it call it something other than TeX.

so if you are, for example, writing a class for some journal or publisher
then the use of LPPL makes a lot of sense, since it really doesn't help
your users if somebody thinks that your "margins", say, are having far too
much space, and is therefore distributing the package with changed values
under its original cover (perhaps with some comment saying so in the file)
and then a user writes an article to fit the required 8 pages an>

d at the publisher it comes out as nine or ten as there they use their
original version of the file.

none of the above licences would prohibit this kind of behavior and soon you
might find different versions in different distributions making reliable
exchange and communication difficult to impossible.

so you have to take your pick: for certain type of programs, GPL etc etc are
by far the simpler to use and probably more appropriate licenses, for
language extensions (and LaTeX code usually falls in this category) LPPL in
my opinion is the better choice, but then I'm biased.

cheers
frank