It means if thread A does an RPC to a remote service, and the thread B in that service that's handling the RPC takes an exception, the details are serialized and returned back to thread A where the exception is rebuilt and rethrown, ensuring that in a platform that supports chained exceptions and blocking threads efficiently (e.g. JVM) that you get exceptions and stack traces that cross services.

It's not hard to implement, it's just that the industry kinda gave up on using powerful RPC frameworks with language integration. gRPC is about the fanciest you'll get and that is a clone of Stubby, which was originally written for C++ in a codebase that banned the use of C++ exceptions entirely. So it doesn't try to solve that problem.