List of 235 apps incompatible with macOS Catalina 10.15 Raw (gist.github.com)

A lot of antivirus apps on this list.

What changes are making all these apps incompatible?

This is not a new list in Catalina, you can see this same list on 10.9,10.10,10.11,10.12, 10.13 and 10.14. A quick check confirms the checksums between the 10.13 and version shown here have not changed.