In the file data/d20ogl/paizo/pathfinder_rpg/advanced_players_guide/pfapg_abilities_racial.lst
Some, but not all, of the "Alternate Racial Traits" for Gnomes from the APG are listed. The complete list is here:
"Darkvision" (replaces low-light) is the specific one I encountered, but looking through the file, it seems that others are missing as well. As far as I can tell, the missing ones are:
Bond to the Land
Knack with Poison
That's five out of the twelve listed which appear to be missing.
Feature Request - Please add the missing alternate racial traits to the ones already implemented