For example, looking at src_devkit.zip
- the sources are not in the correct folder structure (somehow half-way flattened out)
- the plugin.xml is missing
- no .iml / .ipr available
The last two bullets seem to the case for all IDEA core plugins.
It would be great if these src_xxx.zip files of the IDEA core plugins would be as complete as the example plugins that are contained within the idea4444-dev.zip file. This would allow anyone to extract the zip file, add the .iml to an IDEA project, and be ready to play around with the implementation of these plugins.