If you're often juggling APK files for backups or sideloading, you might occasionally get things mixed up. Or you might want to ensure that nothing looks fishy. In either case, there is a nifty little Windows program called APK-Info that tells you all about an APK.
When you launch APK-Info it asks you to select an APK file. It extracts the package name, permissions, API level, version, and lets you open the Play Store page.