Zowe: What does this message mean?

You can use your favourite search engine to look for the message. If it is not found, you can search within the open source.

Thanks to Martin Zeitham for the following.

Each message has prefix, which indicates the server or component. For example ZWEL* is Launcher etc.
There is a command ./zwe diagnose -e messageID to get more details:

./zwe diagnose -e ZWED0020I

gave

This code corresponds to the errors related to the Zowe Desktop and the App Server.

To find the description of this error code, refer to the:

Zowe documentation for Application framework
https://docs.zowe.org/stable/troubleshoot/app-framework/appserver-error-codes

You may also explore reports from other users experiencing the same error by searching
https://github.com/search?q=org%3Azowe+ZWED0020I&type=discussions

I found it quicker to look in the Zowe bin/commands/diagnose/index.js file, which has

• ZWEA: Zowe API Mediation Layer (APIML)
• ZWED: Zowe Desktop and the App Server(APP-Server)
• ZWEL: Zowe Launcher and zwe,(Launcher, Launcher error codes, zwe
• ZWES: Zowe Subsystem Services (ZSS) and Zowe Installation Services (ZIS)

And note the ability to see any discussion on the message ZWED0020I in the git repository using

https://github.com/search?q=org%3Azowe+ZWED0020I&type=discussions