Yey! Just got my PCSensor TEMPer1 USB thermometer logging in Linux. It automatically detects and does expose USB HID profiles, but there’s no way to access the data by holding down the CAPS key like it says in the docs.
Thankfully, a search for the device ID (0c45:7401 Microdia) finds ruby bindings for Temper.c by Michitaka Ohno, which conveniently includes the reverse-engineered USB protocol. So I’ve forked this on GitHub, removed the Ruby bits, edited the unit test wrapped it up in a little script that logs the time and temperature to a CSV file. It currently only supports one device, which will change if I ever get another one of these devices (spoiler: I probably will)