Which packages can I safely remove to save space?

Issue: Flash space is scarce on devices with only 4MB flash, and I don't have enough space left to install a package I need. In order to to save some space: Which of the normally preinstalled packages can I safely remove when building an image?

Solution: You can save some space while compiling your own image (e.g. with the imagebuilder) by removing packages that are not needed for your usecase. In order to completely remove IPv6 support and related packages you also need to ask the imagebuilder to do so by also passing this option to the make command: “CONFIG_IPV6=n”.
See also → Build image for devices with only 4MB flash.
See also → Saving firmware space.