"Entry" error on package upload to marketplace

Steps to reproduced error : try and upload the package attached to the marketplace
There will be an error message that says 'entry' 

Context : This is a studio package, where the type was changed from studio to add on manually in the package.xml 

<package type="addon" name="project-nos" version="0.0.0-SNAPSHOT">

Admittedly not a very conform scenario, but relevant to Multilayer, it would be better to have a clearer error message 

To do : Add a clearer message to this kind of of scenario  

AC : I upload the attached, or similar, and get an clear error message