“64-bit time_t on 32-bit architectures to avoid the ‘year 2038 problem’ when the existing 32-bit signed int rolls over.”
The Year 2038 bug is the Y2K sequel nobody wants to think about, and Debian is one of the few projects actually doing something about it. After Debian 13 ships, they’re flipping 6,429 packages to 64-bit time on 32-bit architectures. That is a massive ABI-breaking change across an entire distribution. The reason it matters is that billions of embedded devices running 32-bit processors will still be humming along in 2038, from cars to routers to building controls, and nobody is going to update their firmware in time.