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
These alternate racial abilities are in the Advanced Race Gide, no the Advanced Players Guide. Also, the ARG has not been released yet. This note should probably be added to the current New Sourse tracker (NEWSOURCE-146) for the ARG.
I just checked and these are in the ARG. This tracker can be canceled as obsolete.
Those are implemented in the ARG. Nothing to add or alter.