This is just made to look like Windows 3.1 at a glance but there are many small details that are different from real Windows 3.1 (or even 3.0). For example Windows 3.x do not have a 3D shaded button at the top left corner of windows, instead they have a flat button/square with a thin "-"-like rectangle that has a black outline, white filling and single pixel shadow, like a three pixel tall popup menu (which is intentional since in Win3.x this was supposed to be the icon for applications to use if they wanted to have a dedicated control/widget for showing a popup menu).

Similarly, the mouse cursor's triangular part is smaller, the window corners are missing the "connecting" corner lines, the font is different (in Win3.1 all fonts are bold and the space is narrower), the button shadow color is too dark (this was the case for EGA in Win3.x but this is VGA and in VGA the palette was modified to have a less contrasting shade for the bevel colors), the dialog box (from the first image in the three, not linked in your message) uses the resizeable (but corner lines still missing) border style instead of the dialog box style (which is blue with a white inner line), etc. I'm sure i can find more differences if i spend more time on this and look at Win3.x screenshots, but these are from memory and i think you get the idea :-P.

Sadly, I can't view your images on my device, but I have a '96 Presario that's fairly close in vintage; it has what I presume you are describing. The program resides on a hidden DOS partition on the HDD. While novel, it's a bit unfortunate, as there's no configuration program in ROM, so without that partition (or the multi-disk floppy set) you can't configure the CMOS settings.

I remember some of those old BIOSs that were quite UI involved.

I always thought "This is really neat... not sure it was worth the effort for a BIOS..."

Granted in those days users were more likely to be in the BIOS to do something than today.

Yet, the BIOSes both of the last motherboards i bought (one recently, another 3-4 years ago) had some very elaborate UIs, with skinned menus, star backgrounds and a bunch of other frivolous stuff. I think one even had some sort of background ambient sound.

Keeping with tradition though, the "help" screens of every option was as helpful as the "help" screens of my 386DX, Pentium MMX and Athlon64 desktops of decades prior, with entries such as the help for "Select frobation mode: FOO" being oneliners such as "Frobation mode, can be FOO or BARF" (but what the hell does frobation mode do and what do the FOO and BARF options mean?).

I think I still have somewhere a pile of paper booklets that came with old motherboards that have similarly unhelpful descriptions of various settings.

They just skinned their BIOS interface to look superficially like Windows 3.1.