So four of these USB Webmail Notifier devices turned up in a dusty cupboard
in the office.

A quick tear-down shows they contain a super-simple circuit - just a
SONiX Technology SN8P2203SB 8-Bit microcontroller that handles the USB protocol and drives an RGB LED. The SN8P2203SB is an old chip phased out 2010/04/30, superseded by the SN8P2240. They have a supremely primitive USB implementation - basically mimicking a very basic USB 1.0 HID device.

A quick google reveals quite a bit of old code lying around for various projects using devices like this. Most seem to use libusb for convenience - and often 0.1 legacy libusb that. As I'm mainly on MacOSX, the code is not much use since Apple no longer allows claiming of HID devices
and the libusb team decided not to try to get around that.

So to bring things up-to-date, I wrote a simple demo using hidapi
and things all work fine - see the video below.

Now I just need to ponder on good ideas for what to do with these things!

As always, all all notes, schematics and code are in the Little Arduino Projects repo on GitHub.