I have already taken the bottom my librem 13, as I like to act like the average prole, so I can give an initial report on the internal layout and wire runs.
To be honest I took the bottom off to upgrade the memory and slot in an ssd, but I thought it might be some next level autism to write about it. I'm not really an expert on PCB design or laptop internal layouts, but I have taken lots of things apart.
My favourite laptop for build quality is in fact my x200, as everything was covered in a plastic dust/splash proof wrap, meaning everything had remained extremely clean despite it being many years old. I don't really expect anything other than thinkpads to compare to the exceptional attention to detail found in the x200
I did spend a couple of summers during college/high school years churning out workstations and servers wich is also why I have an unhealthy obsession with cable ties, cable tension, bend radius and screw types. People very easily overlook important factors such as cable tension tending towards over taught cables that are both a pain in the ass to perform maintenance on and degrading to the cables lifespan. That said I have no formal training in the matter only habits I have contracted from fellow neckbeards or formulated myself.
It looks like pretty much any other modern laptop internal: A compact motherboard situated in the top left, a respectable battery tacking up the entirety of the palm rest, a single slot for sdram, a minipcie (populated with the wifi card), a 2.5" sata drive and an m.2 sata connector to the right. As you would expect of an i5 their is a fan positioned in the middle exhausting heat out of a rear vent from a thick copper heat pipe. The rear vent appears to be unfiltered and run right the way along the back of the case. The heatsink had a small block of what looks to be thermal transfer foam to utilize the metal bottom cover; the bottom of the laptop gets warm.
There was a fair bit of that matt black tape in use to keep wires in place, mostly around the wifi module. It seems that some of the cable could have been made a little shorty for tidiness, but it might be better in the long term for maintenance. The wires for the cmos battery were not afflicted by the tape but had been looped affectionately round the connector in one elliptical coil; I dare not touch it for fear that it would never go down again.
The screws attached the board to the case seemed to be small black painted screws. I didn't look around closely for a ground other than the one for the wifi card which was a wire with the end trapped under a screw, not a screw one would ever have reason to remove so it's fine with me.
Populating the M.2 sata
It's a standard insert at 45 degrees then lower to horizontal and screw affair. The only niggle is that they don't seem to populate the screw hole if you don' order it with a M.2 sata drive; I had to find my own screw.
Changing the RAM
They had put some kingston memory in there which is fine; I just wanted more than I had ordered with the machine. There is only a single dim slot that works in the way you think it does if you have changed ram in a laptop before. I went for a 1.35v dim I think that is what was in there I didn't check.