Apple has pushed an update today to the data files used by XProtect, bringing its version number to 2131, dated 17 September 2020.
Apple doesn’t release information about what these updates add or change, and now obfuscates the identities of malware detected by XProtect using internal code names. XProtect’s Yara definitions include new rules to detect MACOS.449a7ed and MACOS.d444820 and modifications to the existing rule for MACOS.2070d41.
You can check whether this update has been installed by opening System Information via About This Mac, and selecting the Installations item under Software.
A full listing of security data file versions is given by SilentKnight, LockRattler and SystHist for El Capitan, Sierra, High Sierra, Mojave and Catalina, available from their product page. If your Mac has not yet installed this update, you can force an update using SilentKnight, LockRattler, or at the command line.
I have updated the reference pages here which are accessed directly from LockRattler 4.2 and later using its Check blog button.