When loading our plugin for Xojo on MacOS 10.15 Catalina, you may have seen such a dialog.
We now made a notarized version of the download: MBS-Xojo-Plugins193-notarized.dmg
This plugin download is notarized. We removed a few old examples with compiled code, but otherwise the same.
We hope to be able to notarize all downloads in the future for our 19.4 release to avoid friction.