Steps to reproduce

1. Given a stored property foo=en_GB (e.g. from the old UI framework, bootstrap file)
2. Try to load this property with new framework
   1. Use a select field with the datasource named available-locales
   2. TODO add example config for convenience

Expected results

The value is loaded into the field.

Actual results

TODO

Workaround

Migrate the data (e.g. en_GB to en-GB).

Development notes

• info.magnolia.ui.datasource.locale.LocaleSelectFieldSupport#defaultConverter uses the new java format, LocaleUtils from apache might be able to read both fromats
• available-locales datasource __ is not documented _https://docs.magnolia-cms.com/product-docs/6.2/Apps/App-configuration/Data-source-definition.html_