Mages in collars can do the same magic as mages not in collars, mages not in collars can just do it whenever they want without needing someone with their collar's control to let them do that piece of magic in particular.

For Elvira: Bar can supply a few publicly available codes, including with what-the-legalese-means summaries for the ones that have that. "You can borrow these for free."

For Mikoto: She'll skim through a few more things about collars, but if that's not fruitful turn to figuring out how technology interfaces with magic in general - she achieved cutting edge results in a number of fields in under a year with technology centuries ahead of her time, she's confident she can reverse engineer the collars fairly trivially, even if she can't make them without magic. 

"Thank you, ma'am." She'll look at those.

Collars themselves aren't much of an example of technology interfacing with magic - there's some technology involved, but technology isn't considered dependable enough for most of it. And collars have a long development history before modern technology existed at all.

But there is definitely a lot of magic-technology interfacing! Mages can be taught to read information they obtain by magical investigation into a computer readable format. They can also work on technology. Having magic involved has meant this world has some technologies, like real-time translation for spoken conversation, that Mikoto may (or may not) know were not available at the parallel time period and tech level without it.

For Elvira: The codes are all translated into English terms she's familiar with.

For Mikoto: She'll try to poke more at collars, but for now it looks like she's finding a meta-mage - hopefully security will have someone, that collar should be hardly safe.

Information on collars continues to be bereft of any 'how to take off collars in three easy steps' contents. 

It is possible to remove a collar without replacing it; if she can get not publicly published materials she can even find descriptions of how to do it. They do involve magic though. 

She looks at codes (for practical matters; she understands magic can also work differently in other worlds but that is not what she's looking for right now).

This place seems to have not invented collars with permission capabilities. In lieu of that they keep the mages in restraints that prevent magic use except when they're working, arm their minders with crossbows whose bolts prevent magic use if fired into a mage, and kill mages above a certain power threshold in childhood. In rules diverging from ones she's familiar with, their mages aren't allowed to have names. Not even serial numbers (they seem to have something like serial numbers, but the mages aren't allowed to use them or even find them out).

This place seems to not have one unified approach to mages across the world. This one group uses a lot of restraints (that also work partially like a net) and masks. They sometimes sew their mages' lips closed or cut out their tongues. Mages who were out of range of a minder are executed. The mages are used as weapons.

Another group keeps their mages in fortresses. The mages study a lot and do research, but also learn fighting. There's some kind of intense testing event you're really not supposed to fail. There's a punishment that involves having your emotions and magic cut out. They also have group punishment executions.

This place seems to have two kinds of power haver (three?), only one of whom are mages. They keep their mages in something like villages. They're allowed to have families, though there's very strict rules about declaring all children born. They seem to get quite a lot of leeway, by her standards, as long as they're respectful and show up for work and cooperate with some kind of power-drawing thing their humans use them for.

Well. Apparently aside from being terrified there's also being terrified in whole new direction.

Inside her head she can react to things. She's not really that attached to name use; does kind of really prefer having more interesting work if she can get it. Combat is interesting, though she's not opposed to studying or anything. She continues to really not want to die. Also doesn't want to have her tongue cut out, though apparently on the scale of things that can be cut out there's much worse available.

She's not, of course, expecting it to matter (unless maybe there's some kind of situation with multiple parties and there's some way she can try influence it that won't end worse than any of them. Or unless she decides something is so bad she wants to risk trying for the door. (Maybe for the ones with the out-of-range execution, if they'd count her for it, if her chances are good enough to risk dying much more painfully if she fails against dying for sure if she doesn't try.))

(She's good at making herself function under terror. Conveniently.)

Mikoto, having finished reading everything she could find that's potentially relevant and moved to reviewing the scientific and engineering publications she'd been reading before this mess, turns to Elvira once it seems she's done.

...What the hell did she read that has her this scared.

Mikoto reviews her half-paid-attention-to memories of Elvira's half of the conversation, and doesn't sigh but it's close. It seems Elvira is flatly refusing to believe not everywhere has any concept that anyone needs to be forcibly controlled.

"Most worlds don't work like yours. I understand that people in your worlds, and ones you've found that're similar, might work that way. But those codes don't apply here. Milliways is sometimes host to people who can imagine planets out of existence. Your powers are not that strong. Milliways manages to keep the peace despite having, as far as I can tell, exactly two codes that apply to patrons - 'don't be violent in the main room' and 'don't be naked in the main room.' It does this by ensuring there's always someone on security who could stop anyone violent, and that people who will immediately start fights don't get doors. I can guarantee, if we removed your limits entirely, whoever is on security would be able to handle even the cleverest, greatest expression of your power. Survey ships in my world have weapons that could lay waste to a continent in seconds. Everyone easily has access to extremely potentially dangerous technology. If you can't blow up a planet, no one will be particularly concerned about your power levels being a threat. There's worlds with interventionist gods who simply don't let tragedies happen. There's a death world where no one has any rules, but there's automatic resurrection if people die. There's worlds where it's physically impossible for people to interact with each other non-consensually. There's here, where if you stay in the main room no one can hurt you, and where the people in charge as far as I can tell are omnipotent beings who care mostly about facilitating interesting meetings."