This extension has a collection of form fields which can be used in other extensions. For example the Search Action Designer uses this Form Field Library to provide field types on the form after a search.
Below an example of the Message Template field and the Option Group field. The latter is configured to show the activity status.
Below the configuration screen of the Message Template field.
And below the configuration of the Option Group field.
The screenshots are from the Search Action Designer extension and the forms are implemented in that extension, however this extension provides helper functions to implement easily fields.