My guess is they're generic skills, undefined other than the effect. In the Designing Foes section of N.O.W. and N.E.W. you'll see other such skills listed with asterisks (combat skill*, movement skill*, social skills*,etc.) Basic skill sets that a GM may need during play can be generalized as such. In my mind it allows the GM a bit of freedom to define what the skill looks like in the narrative.
Sometimes entire categories of skills are referred to instead of single skills. When this happens, the category is noted in square brackets in order to avoid confusion. For example, an entry which says [outdoor] refers to the entire list of survival, animal handling, tracking, farming, mining, and any others.
Skill Notation as you just said has [brackets] around it. I didn't mention anything about brackets. From N.E.W.:
In particular, the following skills should be calculated:
combat skill* - the monster equivalent of unarmed combat is simply called combat.
perception - this may be named after the creature’s special senses, such as scent, hearing, etc., or it may juts be called perception.
movement skill* - this may be running or some similar skill.
tactics or reactions - the monster should have one of these two skills.
social skill(s)* - this optional skill, especially for tricksters and supporters, might include bluffing, intimidation, persuasion, and so on.