Note that the examples of non-code output are ultimately still code - just not code written by the senior engineer. Part of what an effective senior person does

Note that the examples of non-code output are ultimately still code - just not code written by the senior engineer. Part of what an effective senior person does is to take their own knowledge and wisdom, and externalise it in ways that let their colleagues take advantage of it without having to learn it from scratch. One of the most obvious ways of doing this is writing reusable code. Maybe you know the ins and outs of reliably spawning a child process in OS/2; you write a spawn_child_process_os2 function which does it, so others can take advantage of it. But there are less obvious, and sometimes more powerful ways to do this. The example of an RFC process externalises the engineer's understanding of how to rigorously think through and effectively communicate large changes. The example of security check-ins externalises the engineer's understanding of how to write secure code. The example of a platform team externalises the engineer's understanding of all sorts of code and build details particular to the organisation.