If a PKG file is associated with a Managed Installation, the page will report "This software will not be installed. In my tests, PKG files actually will attempt to install so this message is erroneous and confusing. However, the official recommendation is still to place PKG files in a ZIP file when using them for Managed Installs. If there is still some issue with uploading "bare" PKG files in use with Managed Installations, please resolve. Or, if there is actually not an issue with that (perhaps this only affected old mac OS versions?) then update the web ui messaging and documentation to make it consistent.