Clearly label extensions imported from Packagist
To avoid raising false expectations among inexperienced users, extensions that have not been explicitly published by the author in the TER must be clearly labeled.
For example, the following warning (similar to the "Outdated extension" warning) would be conceivable:
"Imported extension This extension has not been explicitly published in this extension repository. Be aware that the documentation, flexibility and maintenance of this extension may be of lower quality."