android.intent.category.LAUNCHER

• The ACTION_MAIN action indicates this is the main entry point and does not expect any intent data.
• The CATEGORY_LAUNCHER category indicates that this activity's icon should be placed in the system's app launcher. If the <activity> element does not specify an icon with icon, then the system uses the icon from the <application> element.

These two must be paired together in order for the activity to appear in the app launcher.