opentabletdriver/opentabletdriver is an open-source user-mode tablet driver that runs on Windows, Linux, and macOS. User-mode refers to a way of working as an ordinary program rather than being installed in the kernel. The latest release found on the GitHub repository is v0.6.7.
The README states that this project aims for high compatibility and an easy-to-configure graphical interface. It is a real hardware driver that implements tablet input handling and pressure values, button mapping, and device debugging, and its structure splits into two parts. OpenTabletDriver.Daemon processes the tablet data, while the platform-specific OpenTabletDriver.UX.* takes care of the graphical interface. It provides support for multiple tablets, settings saving, plugin functionality, a standalone daemon, and installation guides for Windows, Linux, and macOS. The implementation language is C#, the license is LGPL-3.0, and the repository has 4192 stars.
However, the way pressure output is supported and the conditions it needs differ from one operating system to another, so it cannot be carried over to a different operating system as it is. The changes in v0.6.7 and the release notes are not included in this record, so they have to be checked on the release page. The momentum score recorded as an activity signal comes to only 3.0 out of 10. It is clear that this is a driver dealing with real hardware, but what this version actually fixed is hard to judge from this information alone.