How to create a package for Native C++ plugin of InDesign for Adobe Exchange?

I have developed an InDesign plugin using SDK and C++. The built plugin needs to be placed in Plug-Ins folder. We generally use pkgbuild and productsign on MacOS terminal to prepare the package / pkg. However, I am unable to upload this package in Adobe Exchange approval for distribution. 

How do I create installable plugin to be uploaded for Adobe Exchange distribution?

Also, need to understand whether I need to have any security to be implemented for subscription of this plugin or Adobe will handle its expiry?

Please advise.