After KDBUS failed to make it into the mainline Linux kernel more than one decade ago as an in-kernel version of D-Bus, BUS1 was proposed as a clean sheet design for in-kernel, capability-based inter-process communication (IPC). BUS1 didn't gain enough traction to make it to the mainline kernel and then many of the same developers devised Dbus-Broker as a more performant D-Bus user-space implementation. Well, as a big surprise now, a new version of BUS1 is being worked on for the Linux kernel...