Does Ubuntu have a copy of the kernel source?

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http://askubuntu.com – Does Ubuntu have a local copy of the kernel sources? I'm looking for a copy of https://github.com/torvalds/linux/tree/master/drivers. On other distros it's often in the /usr/src directory, but on Ubuntu I just see makefiles. Do I have to check it out from kernel.org myself? (HowTos)