WAB team please consider keeping WAB URL parameter support in step with AGOL map viewer capabilities.
AGOL Map Viewer: Use URL parameters—ArcGIS Online Help | ArcGIS
There is one in particular that is essential for me to start using WAB in production:
For that "Find location or feature to open map" functionality to work, I'd need to be able to define custom searches within the app, as the AGOL map viewer allows. Is that possible?