The rules as presented are light-weight. Characters have Attributes but the only examples in the Quick Guide are Fitness, Agility, and Charisma. Characters have Skills--defined skills include: Brawl, Dodge, Martial Arts, Listen, Wrestling, Gun, and Sneak. The game infers characters can have any Skill they desire.
A Skill score of 1-2 represents an intelligent but untrained individual; 7-12 indicates a normal, skilled range; 15+ indicates exceptional ability. Skill resolution is 2d6 plus Skill modifiers; a roll of double 1s is always failure and double 6s is always success. Typical Difficulty scores noted are: Very easy - 7; Easy - 10; Average - 13; Hard - 15; Very Hard - 18. If the action is opposed (as in combat) then the Difficulty score is the opponent's relevant Skill roll.
An associated HTML page notes conversion methods to move 3d6 and d100 Attributes into the Lucky 13 system.