The Windows Defender brand changes reflect Microsoft's latest cross-platform security, initially in March 2019, when the company launched anti-virus software for macOS on its own behalf.
In the Windows 10 20H1 update of Build 18941, the names of some Windows Defender components have changed. Windows Defender Exploit Guard provides intrusion prevention for Windows 10 and is now called Microsoft Defender Exploit Guard.
There are already users who have found a folder called "Microsoft Defender Antivirus" and "Microsoft Defender Exploit Guard" in Group Policy. Other features such as Windows Defender Applications Guard have not been renamed, but sooner or later all Windows Defender services will start using the Microsoft brand.
In the support documentation, Microsoft Defender Exploit Guard is still known as Windows Defender Exploit Guard.
Obviously, Microsoft wants to use its company name for services on multiple platforms. For example, Microsoft's Android app launcher is called Microsoft Launcher, not just Launcher or Apex Launcher. Similarly, Microsoft uses the Microsoft brand for antivirus solutions for macOS.
Microsoft still confirms that the new name of Windows Defender and whether it will retain or change brand changes in Windows 10 20H1 remains to be seen.