If you try to apply
the UI5 official method of loading debug sources, you will notice that within SAP Work Zone, it has no effect on your custom UI5 applications or cards.
This doesn't work:
https://<wzhost>/site?sap-ui-debug=com/example/my/custom/card#workzone-home
The reason for this, is that the custom content is running in an iframe and we need to instruct the SAP Work Zone shell (technically, I belief this is to be a SAP Fiori Launchpad) to pass certain parameters to the iframes. The magical undocumented, parameter for this is
sap-iframe-params.
This works:
https://<wzhost>/site?sap-ui-debug=com/example/my/custom/card&sap-iframe-params=sap-ui-debug#workzon...
I hope someone from the Work Zone team can pick this up and include this information in the
SAP Work Zone Developer Guide.