Provides a plugin type for extra fields in entity view. This module allows developers to add custom output to a view mode by simply providing a plugin. This output is treated like a field, site builders can use these extra fields in entity view modes. Extra fields typically combine entity data and format it for display. Extra fields do not store data and do not have a field widget. Extra Field is like a custom Display Suite field, but without the overhead. Other modules

Just wanted to let other developers know that this module is affected by this core issue: [#3069578] So you may have problems in combination with layout_builder. This issue should be closed fixed when the core issue is fixed & committed. As workaround you can remove the extra fields from "hidden" in the configuration.