First, back to the, related SLiM Thread, I had Success, after "apt install xinit" (required package, but not selected).
My next bootup brought up an intriguing Startup Screen that I hadn't seen before, but which has, only one Request, obviously modified by Debian, to add the Debian Logo, and with, hard to read (low contrast) request, "Please enter your username", followed by a Blank Strip to enter the Password. Pretty easy to understand for Linux Geeks, at least. Also, under the "L" in "Login:", it displays, "F1 select session". Now, for contrast, here's what I encountered, when I installed SDDM with KDE: A Split Left/Right Screen (it's a Good HP Monitor, on a Desktop). On the left is the Time, with the Date underneath. But, on the Right, it wants me to "Select your user and enter password". And there are a bunch of, in effect, Statues, only identified with the "Given Name" field of the User Definition. Okay, I can see how SDDM might work in a REAL Multi-User Office Setting, with a Shared Computer, and when the Multiple Users have Distinct Names. But, in *my* case, the "Multiple Users" are, actually multiple *Functions*, with separate Home Directories for, say, devel (Kernel Development), music (Classical Music research), and hercules (a Package to Emulate IBM Mainframe Computers, which works well on Debian buster, by the way). HOWEVER, in my case, all these "extra usernames", share my own Given Name, which makes SDDM quite Confusing. So, when I saw this thread about SLiM, I got excited. And I still am. Even enough, that I may make this my first Linux Package to Maintain. Anyway, before I burn "SDDM Bridges", is there anyway to configure it to refer to Username, instead of "GIven Name"? Thank you, Kenneth Parker