> Each time you convey a covered work, the recipient automatically receives a license from the original licensors, to run, modify and propagate that work, subject to this License. You are not responsible for enforcing compliance by third parties with this License.
Right, but suppose you disappear. The third parties are using code with your modification. Do they have to host anything? They did not modify anything themselves, but there is no upstream any more for the exact code they are using.
> Each time you convey a covered work, the recipient automatically receives a license from the original licensors, to run, modify and propagate that work, subject to this License. You are not responsible for enforcing compliance by third parties with this License.