The important part of a wizard's job in the Risen Guard is to cast Transmutation spells on warriors. Day in and day out: Enlarge Person, Ashen Path, Haste, Fly. The majority of a wizard's job in the Risen Guard is to be in the right place at the right time, just in case. The bureaucratic edifice dedicated to issuing useful orders to competent, well-trained, well-circled men is impressively complex. Those orders mostly pertain to the where and the when; once you're on call to cast Glitterdust as necessary, the rest of your time is spent watching your assigned choke point.

It's not very intellectually stimulating, and the people who do it are not in need of intellectual stimulation. Once you've gone through the early phases of an adventuring career and died once or twice in service to the throne, you develop an appreciation for jobs where the mortal danger has to approach you and foil your plans while you wait in a heavily-fortified location where the archers already have their arrows nocked and the world's largest Antimagic Field is just a stone's throw away. The most complicated thing Risen wizards do most days is prepare their spells.

Nevertheless, one does not become a wizard in the first place without having a knack for problem-solving. The three Osirians wander through the layered Illusions (very impressive, more comprehensive than a Mirage Arcana but not as hard to disbelieve) while taking notes on the individual spells. The color-based representation of a scalar field is unfamiliar, but given that it's possible to distinguish some spells but not others they may as well start by assuming the most common ones with major similarities in the 250 meter detection range are the usual suspects (in order: Detect Magic, Guidance, Prestidigitation) and see whether that yields any useful insights.

Phēl watches the Illusion of Lorelei's location bob back and forth as Tanya scrubs through the timeline.

"Was her headband not magical? Were any of the headbands magical?"

"...there was always nonzero magic around their heads and I can't separate out local spells or identify what comes from a magic item except by proximity."

"Hmm."

Phēl removes a very similar-looking headband (by unhooking it from behind the ears) and throws it out the nearest window into the street.

One of the guard wizards makes a strangled choking sound.

"Does mine look like it's emitting magic to you?"

(Ah, Tanya knows that sound. It's the sound of an employee swallowing the words that, yes, any attempted theft would be very inadvisable and doomed to fail but it's their job to chase down the inadvisable thieves and you are making it harder!)

"It does not. Should it? What is it doing?" She regards the headband warily. It seems to be simply laying in the street, but that's what ordinary soldiers think about mage infiltrators!

"...I have seen other - engineered phenomena, on Golarion, which I could not detect as magic. For example, when Abadar hired me this morning, his illusory symbol appeared above my head for a few minutes, like so." She demonstrates. "And he granted me knowledge of how to activate magical abilities, without me detecting any magic affecting my head. I assume such magic is mediated by a different, nonmagical force at its actual target, just as when my thoughts were purportedly being read I couldn't detect any foreign magic near my head."

"It makes you smarter by a few standard deviations while you're wearing it." And it's definitely magical, even while it's sitting on the ground. Between this and the failure of Nondetection, Tanya's definition of 'magic' is more idiosyncratic than she initially let on.

"I'm not terribly surprised that Abadar's symbol appeared to be mundane to you. It's the kind of supernatural effect that isn't responsive to antimagic. Detect Thoughts… isn't. That one ought to be as clear as day." Not that Phēl can tell which part of the color smear is supposed to be the Detect Thoughts. It's like trying to interpret someone else's memory of a blurry impressionist painting after dropping it in the canal. "Does your orb not sense magic when it's stored in an item?"

"I... don't know that magic is being stored in the first place? I would sense a constant magic field. Whatever is stored in the item isn't itself magic, it produces magic. Just like a mage's mind isn't magic normally, but then it produces magic. The translation might well be imperfect; magic is a technical term and our scientists' definition of it might be different from yours. If the item has a reservoir of energy used to produce magic, which can be depleted and refilled or renews by itself over time, I'd call that mana, again by analogy with mages. ...and the word mana translates to Osirian, but I'm not sure what it means to you either." Mana isn't something Earth scientists know how to detect or measure directly, just a name for the empirical ability of a mage to produce magic. If they knew how to detect mana they'd be halfway to generating mana outside of human brains.

"Mana is a property of voluntary interaction with magic," one of the guard wizards comments. "We used to think it was intrinsic to having a soul, but there are at least a few counterexamples. If you're looking for an intermediary, that's one option. When you watch someone cast Detect Magic, does it come out as just the spell in their hands, or can you also see the cone-shaped resonance field that picks up auras and feeds the information into their brain?"