It would be great if you could create a custom_templates directory inside of a package that would allow you to separate your macros so that they could live with the package they are relevant for. For example, if I have a power_mgmt package that is focused on sensors, automations, etc. for power management I may have a set of macros specifically for that package and it is a bit annoying they have to exist in config/custom_templates/power_mgmt.jinja instead of packages/power_mgmt/custom_templates.
Or at least, it should be possible to create macros in a package’s yaml file, that can be used from that same file. Currently if I want to share a package, I also need to share the macros separately and ask people to add them to custom_templates.