As discussed in https://github.com/twbs/bootstrap/issues/15117#issuecomment-63029993
- added
scope="row"to row headers (can be either<td>or<th>, AT doesn't care much) - removed
scope="col"where it was redundant - simplified table examples with (to me) unnecessary
rowspan/colspan(unless you really want complex tables, in which case we would need full-onidandheadersattributes to make sure each table cell has an explicit association with the related header cells - overkill, in my opinion)