The project is called “Tactility” and its website is https://tactility.one/
You can run ELF binary apps directly from an SD card without restarting or flashing the ROM. There’s an SDK for building these apps, but I haven’t made an official release yet.
I wrote a blog post with some background information: https://bytewelder.com/posts/2025/01/06/tactility-one-year-later.html
Source code and project files: https://github.com/ByteWelder/Tactility
Looks cool! However, there is with badge.team also a similar app platform which they used on https://flow3r.garden/, on the MCH22-badge and the now in preorder namatsu: https://shop.nicolaielectronics.nl/products/tanmatsu?variant=55608856183133 (which I just ordered two of)
While it definitely is a cool project, it’s a micropython one, so the target audience is similar but not the same.