Magic Sense (Magus) Feat 12
Source Pathfinder Secrets of Magic
You have a literal sixth sense for ambient magic in your vicinity.
You can sense the presence of magic auras as though you were always using a 1st-level Detect Magic spell. This detects magic in your field of vision only.
When you Seek, you gain the benefits of a 3rd-level detect magic spell on things you see (in addition to the normal benefits of Seeking). You can turn this sense off and on with a free action at the start or the end of your turn.
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
ArcaneThis magic comes from the arcane tradition, which is built on logic and rationality. Anything with this trait is magical.
DetectionEffects with this trait attempt to determine the presence or location of a person, object, or aura.
DivinationThe divination school of magic typically involves obtaining or transferring information, or predicting events.
MagusThis indicates abilities from the magus class.