Here is the code for a 69 character answer

/// 73 characters:
/// f x=a,b{f i=65:1:90{s $li(x(x),i)=$l($zcvt(x,"u"),$c(i))}} q x(a)=x(b)
/// 
/// but this one is 69:
/// 
/// loop ascii number from "A" to "Z" and "[", that's 65 to 91
/// if count of each letter in each string is different then quit loop
/// if loop reached 91 then loop completed and letter counts must be same in both strings
/// if loop didn't reach 91 then must be counts must be different
ClassMethod Detector(As %String, As %String) As %Boolean
{
 i=65:1:91{q:$$r(a)'=$$r(b)i=91
r(x)$l($zcvt(x,"u"),$c(i))
}
 

I'm a fan of beyond compare but it is not always available on some of the sites I log in to. I'm not a fan of RCMP. I've got a Diff program that works in a terminal session that I use when I log on to a Cache version 5 site. Feel free to take this and do what you want with it (.MAC routines can be found on ^rMAC):

 
Code

I was going to play but it is difficult to get started.

Tried to get the template, downloaded git and Docker desktop, got a git account, got IRIS working through Docker - was quite impressed with that) but cannot get the template. Am getting at least 2 errors on "docker-compose build" command:

Is it possible to play without the template? Surely it's just a class in UDL format?

The day 1 problem is easy to solve. I expect most of us could do it in one line of code. But what are the rules? How does the scoring work? Is it a race? Do you need to be in the first 5 people to finish it every day? Is it judged by someone? If so, what are you looking for? If you can't get your entry in on day 1 will you be too far behind?

Going to try it on a MAC instead of Windows, maybe that will help.