Currently, the "Header orientation" (meaning whether the first row, first column or both are headers) is a setting in the field formatter.
However, this isn't so much a display setting, as a setting about the semantics of the table data.
For example, technically, you could have the "Header orientation" be "First row" on the "Default" view mode, but "First column" on the "Teaser" view mode on the same content type. But for the same table data, that doesn't really make sense: the first row or first column are headers or values semantically, ie. it's just part of that specific table data.
Also, it'd be nice to have a tables of different "Header orientations" on different nodes of the same content type, as opposed to having to have a separate content type or field for tables with horizontal vs vertical headers.
Is this something that this project's maintainers would be open to?
I saw reference to doing this on the Drupal 8 version here:
#3019613-24: Move display related settings from manage fields to manage display and add options →
What about on the Drupal 7 version?
The challenge for Drupal 7, of course, is the upgrade path, because there are lots of existing sites out there where this is only a field formatter setting, and maybe some of them don't want this configurable per entity. I'm not sure the best way to handle that, so just starting the discussion here first.
Thanks! :-)