To avoid confusion, striking through old description. This is now a DOC ticket. We just need to document that the layout for the switchables in switchable field can be changed to horizontal when using the field in definition and that it otherwise defaults to vertical.
Switchable Field: Default should be horizontally how it was in M5. The current default is vertical - looking at the documentation, the switchable field is missing the layout property completely:
Option Group: According to the documentation here orientation should default to vertical. Now it seems the default is horizontal.
Option Group is fixed already in 6.2.2.