workflowReferenceName ?

[capoaus75]

In my Test Environment I have a Power Automate that calls a child flow "Run a Child Flow".
In the dropdown I can select the Child Flow name and everything is working as expected. 
 

Because I am importing my solution as a managed solution in the test environment I would like to set up an environment variable instead of selecting the Child Flow from the drop down.
I copied the run a child flow action to my clipboard and pasted it in notepad. I can see that the code refer to:

"operationName":"Run_a_Child_Flow","operationDefinition":{"type":"Workflow","inputs":{"host":{"workflowReferenceName":"e6631ffa-0dd0-ec11-a7b6-002248943c2a"}

So instead of selecting the Child Flow name from the dropdown I passed the GUID and everything works fine

Where can I get the GUID used for the workflowReferenceName because that is not the GUID of the workflow that you get from the URL when you edit the Child Flow.

Thanks