As per an internal JIRA GRANITE-29559, it has been decided to remove Package Share integration from AEM due to some security issues. Package Share Icon is removed from the following in latest AEM 6.5.5 patch, and so the reported behavior is expected :
- com.adobe.granite.crxde-lite
- com.adobe.granite.crx-explorer
- com.adobe.granite.platform.welcome
- ui-touch-optimized
- ui-classic
- ui-classic-welcome
- com.adobe.granite.crx-packagemgr
Hope this answers your query!!