Re: PG 13 release notes, first draft

|Allow function call backtraces of errors to be logged (Peter Eisentraut, Álvaro Herrera)
|Server variable backtrace_functions specifies which C functions should generate backtraces on error.

I think the details in the description are eclipsing the most important thing:
backtraces on Assert().  I would say "Support for showing backtraces on error".

Regarding this one:
|Add system view pg_shmem_allocations to display shared memory usage (Andres Freund, Robert Haas)
|WHAT IS THE ENTRY WITH NO NAME?

There seems to be two special, "unnamed" cases:
src/backend/storage/ipc/shmem.c-        /* output shared memory allocated but not counted via the shmem index */
src/backend/storage/ipc/shmem.c:        values[0] = CStringGetTextDatum("<anonymous>");
...
src/backend/storage/ipc/shmem.c-        /* output as-of-yet unused shared memory */
src/backend/storage/ipc/shmem.c-        nulls[0] = true;

That seems to be adequately documented:
https://www.postgresql.org/docs/devel/view-pg-shmem-allocations.html
|NULL for unused memory and <anonymous> for anonymous allocations.

I would remove this part:
"Previously, this could only be set at server start."

-- 
Justin