A new version of TIAGo simulation sources packages were released a couple of months ago. The packages were removed from the ROS buildfarm as there are some pending merge requests to some dependencies that prevent them building properly. As explained in http://wiki.ros.org/Robots/TIAGo/Tutorials in order to have the simulation it is necessary to do an installation from sources. Nevertheless, the old debians ros-indigo-tiago-* for Ubuntu can still be installed.
Until we are able to release the new packages can the old debians be removed?
Packages released onto the build farm that are then removed will eventually age out of the repository. They do not get actively deleted.
When packages are removed from the index, they will no longer be built. But they won’t get removed from the repository until a package that depends on them gets rebuilt and invalidates them.
I think in your case the packages have mostly been cleared, and those that are not cleared will be cleared in the next indigo sync, which is pending.
I will note that the sourcedebs will not automatically disappear.
And of course if you’re behind any apt caches or mirrors then it’s quite possible that the packages will not be removed soon or ever depending on their replication policies.