Summary

Extension adds a high level Hub page that:

Allows a user to select a a pipeline containing a JSON schema that defines variables
Renders a HTML Form using rjsf, that includes validation of fields
A number of Azure DevOps specific widgets are mapped (Identity pickers, current user, current project)
Once the form is filled out, the associated pipeline is run by passing the JSON variales to the pipeline variables
The pipeline variables are presented as a flattened JSON key-value object, e.g. "contact.address.street_name" : "main street"

User Guide

Please see here

Dev and Architecture (including Open Source/3rd party libraries)

Please see here