In the source book 'Guide to Pathfinder Society Organized Play' the Dark Archives Faction Trait 'Librarian', does not provide an option to select a skill, which prevents the appropriate bonus and class skill indicator being set.
The Content in the pathfinder_pfs\paizo\pathfinder_society\organized_play\gtpsop_abilities.list is correct, but incomplete.
to make this trait work the way it is described, it is necessary to add the following to the Librarian (Dark Archives Faction) trait
MULT:YES CHOOSE:SKILL|Linguistics|Profession (Librarian) BONUS:SKILL|%LIST|1|TYPE=Trait CSKILL:LIST SOURCEPAGE: p.14
Please Note: this data issue did not exist in PCGEN 6.02.1 RC3, as the Dark Archives Faction did not exist at that time. Dark Archives Faction was added in Season 6 of Pathfinder Society. (approx August 2014)
N/A - Purely a Data Issue