the new version of langprefix
With language codes he seems to think that it's inherently better to make a template break when the wrong code is used, instead of using policy to restrict usage. Which I think is naive, considering that there are always workarounds. Here's one! bīdanan :)
Personally I think the best solution that will cause us the least headaches in the long run is by having all code templates (except scripts) share a single common naming scheme. Including templates for families, so that we can eliminate the #ifexist's from {{etyl}} and {{derivcatboiler}}. We already have an alternative for figuring out what 'type' of thing the code refers to, the /type subtemplate. If we decide to rename the templates, we could also decide to prefix them all with something like code: or code/. That would them allow us to use any template name freely without worrying whether it conflicts with a code.