I've used many flavours of unix since 1980 and Linux since 1992, I have yet to see one that echos anything back to the screen.
Here is the link to RFC86 which was the Pluggable Authentication Modules, but I can say that before that I had never seen a password echoed on any of the many versions that I had worked with.
These included DG's MVUX and DGUX, Dynix, Olivetti Unix, CT Unix and a number of others.