It includes all the settings related to Windows Defender. The application, formerly known as 'Windows Defender Dashboard' and 'Windows Defender Security Center', has been created to help the user control his security and privacy settings in a clear and useful way. Recent Windows 10 version come with is a new app called Windows Security. Microsoft is renaming the app Microsoft Defender.
In Windows 8 and Windows 10, Defender is based on the Microsoft Security Essentials app which offers better protection by adding full blown protection against all kinds of malware. Earlier versions of Windows like Windows 8.1, Windows 8, Windows 7 and Vista also had it but it was less efficient previously as it only scanned spyware and adware. Windows Defender is the default antivirus app shipped with Windows 10. Also, the OS won't receive performance and feature enhancements. It's obvious that the device can become vulnerable to malware over time.
When a connection is set as metered, it prevents most of the updates from being downloaded and installed.
