The SR5 origins quick start rules mention "infiltration" + INT on Infiltration Test (p.4, under skill ratings) and again on p.7 under opposed test notation, interestingly saying to sneak past a guard, roll Infiltration +AGI [physical] (which, to my understanding is Sneaking, not Infiltration).
The SR5O core rules mentions Infiltration again on p.365 (under Motion Sensors, and under Sound Detectors).
However, the SR50 core rules on p.90 does not mention Infiltration as an Active Skill, nor does Infiltration appear in the skills section (starting on p.130), under any skill type or skill specialization.
Do you think Infiltration is an "interest" knowledge skill (p.90-91), or is this just an error to some beta rules (and Infiltration is now = Sneaking skill)?