When importing a package using the classic experience (accessing AppSource from within the environment) and by using the Package Deployment tool in the SDK, the WelcomeHtml and EndHtml pages in the folder "PkgFolder/Content/{language}" are displayed before and after the import respectively.

This content doesn't show in the PPAC package import experience, likely due to the asynchronous nature of the install experience. Please provide a way for these content pages to display to the admin in their proper timing, before and after import. This is needed for ISVs to message the installer before and after the package deployment.