[byvirtueof]

Had to Google this one: Richard M. Stallman.

[eimrine]

gnu.org - contains everything you need to research his philosophy.

stallman.org - personal website, contains a lot of opinion, but I absolutely respect this man in all what he says.

emacs.org (redirects to https://www.gnu.org/software/emacs/) - his non-philosophical work, one of two mainstream text editors for *nix.