This is really just a driver which sends a bunch of bytes via I2C to a microcontroller.

I2C is a very standard way of communicating with digital integrated circuits at low speed so this is not specific to the microcontroller used on Synology NAS devices (which is actually a pretty old and simple one) much less specific to drive leds.

So whilst technically this specific Linux Driver ends up controlling LEDs on a very specific device, the technique used in it is way more generic than that, and can be used to control just about any functionality sitting behind a digital integrated circuit that exposes an interface to control it via I2C, be it one that hardcodes it or one which, like this one, is a microcontroller which itself implements it in code.

All this to say that this is a bit bigger than just "LED driver".

Synology... They are enshitificating at great speed. https://www.tomshardware.com/pc-components/nas/synology-requires-self-branded-drives-for-some-consumer-nas-systems-drops-full-functionality-and-support-for-third-party-hdds