The folks behind Debian LTS and Freexian ELTS are all Debian members/contributors, and the Debian LTS changes end up in the Debian archive, while the Freexian ELTS ones are publicly available, just in an external archive.

https://wiki.debian.org/LTS https://wiki.debian.org/LTS/Team https://wiki.debian.org/LTS/Funding https://wiki.debian.org/LTS/Extended

I think they mean the LTS kernels, not Debian's LTS.