Contains a set of fields and methods common to items of any app (see BaseApplicationItem). This set can be extended with fields and methods specialized for items of specific apps.

Contains a set of fields and methods common to reference objects of any app item (see. BaseApplicationItemRef). This set can be extended with fields and methods specialized for reference objects of specific app items.
Reference objects are generally used in App type properties to avoid loading all related data at once. To retrieve the full data of an app item, you need to call the method BaseApplicationItemRef.fetch and obtain the full object of the item ApplicationItem.

const  my_app_full = await Context.data.my_app.fetch();