The "ahnentafel_on" variable should be left blank. It's for constructing a phrase like:
John Smith was born on 13 April 1877 in someplace, somecountry.
The problem is that there's no easy way to determine whether the date is exact or not, because when the date is not exact (just the month and year or just the year), the word "on" should be "in". Also, the word used can vary according to other context in other languages. The variable should really be removed completely.
The various "accesskey" variables define keyboard shortcuts to make the browser call up different pages just by holding down the "alt" key and hitting the letter. I'm not so sure that this is a good idea -- my preference would be to get rid of this feature completely.
This feature is also not well documented. Another problem with the feature is that it does not translate very well, and if you attempt to choose different letters for your language's implementation, you could easily choose something that already has a different meaning to the browser (aside from the PGV meaning). Furthermore, the different browsers are already sensitive to various such "hotkeys", so it becomes very difficult to choose something that isn't used by any of the browsers.
and that is consistent across all PGV pages.