macOS Catalina 10.15.4
I followed all steps specific to macOS 10.15 on https://helpx.adobe.com/ca/creative-cloud/kb/installingextensionsandaddons.html#Install_extensions_command_line_tool with no lucky.
Command ExManBridgeTalkCmd and ExManCmd --help worked well.
But ExManCmd --list all, ExManCmd --install xxx.zxp have error.
Abort trap: 6
I googled but no answer was found.
In EMCL.log, it mentioned DB and config.
I have experience by removing ExMan.db to resolve Extension Manager issues on Windows before.
So I tried the same here and it worked.
Rename or move away following folder and files.
/Library/Application Support/Adobe/Extension Manager CC/Configuration/DB/
/Library/Application Support/Adobe/Extension Manager CC/Configuration/XManConfigV2.xml
Hope it helps.
Eric