Changing Licence

Back when GPL3 was being worked on, and it was a (slightly) open question whether the kernel would adopt it, it seemed to me that this type of historical analysis of code history was exactly what was required.

With the ownership of each line of code traced to its author, and an agreed definition of what constitutes original work (rather than just a minor change to somebody else's work) it would be possible to determine who held rights in each file.

If, for example, the GPL2 became unenforceable in China or India, and it was decided that a license change to GPL2++ was required, then permission could be sought from identified license holders and the code belonging to those who were unavailable or unwilling to give assent could be rewritten.