So that doesn't help at all.
If I put:
"objects": { "selectedListType": { "displayName": "List Type", "properties": { "text": { "displayName": "Textx", "type": { "text": true} } } } }
I get nothing.
Telling me to go and search somewhere is also of little help if I have no idea of the location you are talking about.
This is seemingly simple stuff but Microsoft you are making it so hard to understand the basics. You might follow the approach of Mr D3 (Mike Bostock) and offer a plethora of worked examples instead of a few comments which have no context.
Getting a propert to retrun a string value seems SO simple. But where is the simple example that shows how? The solution? Don't have a text input field. Crazy.