Nest made an implicit choice of tools back around 2010 when it selected the particular SoC that powers the early thermostat. Options were more limited then, an

Nest made an implicit choice of tools back around 2010 when it selected the particular SoC that powers the early thermostat. Options were more limited then, and vendors often provides kernel tools and libraries that included proprietary closed-source components. Over the years most of these tools have been abandoned or EOLed by their providers (as companies will do). Keeping these tools working and building new releases of software in the context of a modern build environment is a full time jobs itself, especially in the context of Google with its highly idiosyncratic internal processes. While I was at Google I complained bitterly about the repeated killing Nest products. But there was no way I had the bandwidth (or the permission) to serve as the sole lifesaver for any of them.