Apple today released the second beta of macOS Catalina 10.15.5 to developers for testing purposes. This is two weeks after releasing macOS Catalina 10.15.4 which included iCloud Folder Sharing, Screen Team Communication Limits, and support for real time Apple Music lyrics.
We do not know what is new in this update, but it is likely it will include bug fixes, performance improvements, and security improvements.
We will update this article if we discover anything new in this macOS Catalina update.