When using the Export Records action of the Feature Info widget, the exported CSV file shows the codes and not the descriptions for fields that have domains. The default export behavior should output the description instead of the code for those fields, as it does in Web AppBuilder applications. Currently, with Experience Builder, there appears to be no way at all to get the attribute descriptions into the output table.
The soon-to-be users of the application that I am developing with Experience Builder have explicitly requested the ability to export all of the records in the data to a file (must be a non-proprietary format). Those users will not be able to do their analysis if they receive the domain code values instead of the descriptions.