The soft shiny film is part of a flexible eink (or similar) panel.
The back pops off in the typical fashion with a blade or plastic tool
The insides after going around under the top bezel gently with a thin craft blade as it's glued.
Rear of display and top of PCB with metal cover. As with all eink you can see a faint negative version of image on the rear.
A metal cover gives support to the PCB. It's not stuck or clipped, just trapped. Sorry a bit blurred. Anyway, I can see the 8 G byte Flash memory IC, so no SD card to upgrade like in some other ereaders.
No animals, humans, aliens or ereaders harmed in the taking of photos, i.e. it still goes.
Strange filenames due to using Rakunten's Viber chat to send photos via WiFi from phone to PC.
The JVC LiPoly battery (Cell really) plugs in, so easy to replace if you can buy one and have a small starhead screw driver (may be possible to wiggle in) and know how to pop off plastic covers. The cover snapped back on easily.
I put some medium size (150K to 700k) jpeg ebook covers in a subdirectory called Images. The Picture option on Home page shows list or thumbnails (unlike eBooks where you only get thumbnails of start of a text file). It won't display any full screen; briefly flashes white and very brief "Invalid Format" message.
Maybe they have to be size of screen or smaller?
However it does seem fairly well made and designed and certainly is the most portable eInk ereader. You'd want to only load working ebooks and then it renders fine. Probably using ADE for epub.
I've not investigated the other formats other than the text already on it.
There are TX, RX and GND pins. Maybe 3.3V serial console?