> The letter column allows to have the index entries aligned on the widest > letter. Also having the letter not with a colspan allows to have only > one column for the letter line, which gives an easy to follow structure > when there are borders or coloring of the cells. There is a downside, > though, there are empty cells on the letter column for all the index > entries. But it does not look that bad to me. Another downside, of > course is that there is no possibility to use CSS to remove the empty > letter column. However, with CSS, the effect is not the same as the > indentation is one number, not something lin line with the actual width > of the letters.
It doesn't seem necessary to change this even if there are other possibilities. It seems like a different issue to the implementation of multi-level indices in the HTML output.
