Comment 397 for bug 353877

I can see closing the parts relating to character alignment as WONTFIX. Those are explicitly stated as optional in the HTML4 spec and they would definitely impact performance, especially when the engine has to calculate the character offset. The other attributes only require column inheritance of properties. That was fairly simple in the pre-CSS pre-DOM days as the user agent could know which column a cell was in and always would be. The former is still true and I doubt that there would be many cases where these attributes would be used where DOM manipulations would be done.