Debian Testing complete sources.list

sources.list

deb https://ftp.debian.org/debian/ testing contrib main non-free non-free-firmware
# deb-src https://ftp.debian.org/debian/ testing contrib main non-free non-free-firmware

deb https://ftp.debian.org/debian/ testing-updates contrib main non-free non-free-firmware
# deb-src https://ftp.debian.org/debian/ testing-updates contrib main non-free non-free-firmware

deb https://ftp.debian.org/debian/ testing-proposed-updates contrib main non-free non-free-firmware
# deb-src https://ftp.debian.org/debian/ testing-proposed-updates contrib main non-free non-free-firmware

deb https://ftp.debian.org/debian/ testing-backports contrib main non-free non-free-firmware
# deb-src https://ftp.debian.org/debian/ testing-backports contrib main non-free non-free-firmware

deb https://security.debian.org/debian-security/ testing-security contrib main non-free non-free-firmware
# deb-src https://security.debian.org/debian-security/ testing-security contrib main non-free non-free-firmware

Is there really a testing-backports?

Of course, it is there,

https://ftp.debian.org/debian/dists/testing-backports/

maybe it's worth changing "ftp.debian.org" to "deb.debian.org"?
https://wiki.debian.org/ftp.debian.org

I've got, uh ... sort of an odd question re the testing branch of Debian. I was interested in an upgrade to cmus (a music player); specifically ver 2.11 that was released this past May. I thought, "Why don't I get that from Debian's testing distro - rather than d/l & build from cmus GitHub?" Poking around led me to this page. Can someone please explain why I would be interested in Bug reports from 2016? WTF use or relevance do these bug reports have w/ the 2.11 release??

This is not recommended by Debian!

Remove, disable or comment out any other stable-specific apt sources, like *-backports or *-updates

Source: Debian Testing