The Linux kernel 3.8.x branch was thought to be dead and buried, but Canonical has volunteered to pick up the slack and continue the development.
Canonical adopted the latest Linux kernel for Ubuntu 13.04, which at the time of launch was the 3.8.x branch. In the meantime, Greg Kroah-Hartman, the maintainer of said branch, has deemed that particular branch as EOL (end of life).
“The Ubuntu kernel team is pleased to announce that we will be providing extended stable support for the Linux 3.8 kernel until August 2014 as a third party effort maintained on our infrastructure,” said Canonical's Kamal Mostafa.
Apparently, Canonical is determined to use the same stable request and review workflow, and to follow the standard upstream stable kernel rules.
The Canonical maintained kernel will be a fork of the last 3.8.13 version and it will be available for download from the usual locations.