Re: Um... webkit
Webkit would have nothing to do with Linux as it was a wholesale lift of KHTML (the K coming from the usual source). If memory serves Apple initially would not contribute back to the KHTML project (in fairness the LGPL did not require it) but continued "go on do the right thing" public pressure resulted in Apple doing a massive there-you-go-then undocumented code dump.
"having to release your mod as source isn't freedom at all" fair enough but the you are all free not to use the code you are modding too. It doesn't seem to be serfdom to acknowledge that you got something so you should give back. In general that seems to be called "society"