Actually does anybody have rights to put a copy of the html in their
projects ? That is, if I have a project that proudly uses lua as scripting
language do I have to ask for rights to put a copy of the html manual?
Yes, the Lua license explicitly says so: the "Software" means "this
software and associated documentation files". So you can distribute
the reference manual freely.
But you cannot distribute PiL. The web site says so:
"This online book is for personal use only. It cannot be copied to
other web sites or further distributed in any form."
http://www.lua.org/pil/