This is probably an Acme-brand computer. There is no battery in there. These computers usually house standard AT, ATX or PICMG boards. Basically a standard PC in a luggable enclosure, and it weights around 8-12 kilos depending on the screen size and form-factor.

The display is being fed either using a special videocard with an internal LVDS connector, or some sort of A/D converter card that connects to the videocard using regular VGA.

Basically you can learn a lot if you ask the owner to take a photo of the ports and I/O. You'll instantly know if it's AT and whether it needs a special videocard. If there's a VGA cable outside of the case that plugs into the video card — bingo, you can use any standard mobo and videocard you want. If not — there's probably a crappy C&T or Trident card inside (ATI Rage in best case), and you won't be able to replace the videocard.

Also these machines can have any kind of screen, from monochrome or passive color matrix to active color matrix. I don't think Acme had monochrome, though.It would be perfect if the owner would turn on the computer and try to move the mouse pointer around. If there's a noticeable ghosting behind the pointer, it's a passive matrix. These panels can be replaced, but it's pretty involved.

Tbh I'm not that interested in owning it, I have enough crap and this one is a little too new for me. Imight borrow it and perhaps help sell it if it has any value at all, being a less known manufacturer. I have a feeling the interest is low as it is too new but I agree it might depend on the factors you mention.

I personally think it's a passive color screen as the manual shows a computer with color graphics. Passive displays have both brightness and contrast buttons usually but I can't see any.

Any ideas on its purpose? Is it a cheapo alternative when you needed some portability or a more specialized use case like in a lab where you need special Io cards or something?

There was actually a category whose members were referred to as "luggable" PCs . Dolch was active in that space. These were meant to be more powerful than a laptop while still affording a degree of portability (or luggability ).

EDIT : As jheronimus said, it is an Acme machine, as the barely readable FCC ID ( MQMTD86125P) matches https://fcc.report/FCC-ID/MQMTD86125P