Have a look at the logs on each package build daemons:
amd64 & i386 packages build logs
armel package build logs
armhf package build logs
arm64 package build logs
Have a look at the output on each image/platform build daemons:
amd64 & i386 base images/iso
(internal only)
amd64 cloud image
(internal only)
amd64 & i386 vm images
(internal only)
arm64 base image/iso
arm64 cloud image
ARM SBC
WSL rootfs
Package's health:
CI Overview
Upstream Watch
Other useful links:
Git Activity
Auto Package Test (debci)
Kali Janitor