The GNU GPL is very long. If I have to include a copy of it with my program, can I drop the preamble to save space?
I've just discovered (again), that my question is in fact a Frequently Asked Questions about the GNU Licenses.
The preamble and instructions are integral parts of the GNU GPL and may not be omitted. In fact, the GPL is copyrighted, and its license permits only verbatim copying of the entire GPL. (You can use the legal terms to make another license but it won't be the GNU GPL.)
The preamble and instructions add up to some 1000 words, less than 1/5 of the GPL's total size. They will not make a substantial fractional change in the size of a software package unless the package itself is quite small. In that case, you may as well use a simple all-permissive license rather than the GNU GPL.
From the GPL:
Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
The preamble is just a few percent of the text, I would think it could not make any significant difference, could it?