Version 1.8 of ArcGIS Experience Builder developer edition is now available to download. In addition to picking up features from the online edition March update, it improves documentation with a new topic Use data source in widget, and adds a new entry for Calcite components so you can easily import them into custom widgets. See the release blog for more information.
Cheers,
Updated on April 29: A patch for version 1.8 of developer edition addresses a regression issue
