People don't edit program binaries usually, so let's take a realistic example: I produce a bidirectional bilingual dictionary using some Perl scripts that automatically generate LaTeX source for both sides of the dictionary from a marked up version of one direction. However, just before going to press I notice some errors or bad formating in the final result and I fix those problems by editing the LaTeX source rather than the original source or the Perl scripts. Now, my original source was based on someone else's GPL data, so, what do I have to distribute together with the PDF?
I think I would have to distribute both the original source and the LaTeX source and an explanation of what happened. The preferred form for making modifications depends on the type of modification: to make minor local changes, the preferred form is the LaTeX; to make major global changes, such as adding a lot of new words or replacing one of the languages with a different language, the preferred form is the original marked up source. It's true that the GPL wording implies that there is a single "preferred form", but in this case there seem to be several such forms, and it makes more sense to understand the GPL as referring to all of them rather than forcing a choice between them. Edmund
