With Ubuntu 14.04 shipping the Linux 3.13 kernel and it being a Long-Term Support (LTS) release, Kamal Mostafa at Canonical has pledged that the Ubuntu Kernel Team will take over stable maintenance of the 3.13 kernel series where Greg left off.
The Ubuntu Kernel Team is looking to extend stable support for the Linux 3.13 kernel until April of 2016, or another two years. The Ubuntu developers will be carrying out 3.13.y.z stable point releases over on their Ubuntu.com Git infrastructure. Their 3.13 kernel will be maintained the same as the upstream rules regarding stable kernel point releases. Their extended stable kernel plans are outlined via the Ubuntu Wiki.
Those interested in the continued Linux 3.13 kernel support can read the announcement on the Linux kernel mailing list.