In this Wolfram talk video titled "Professor Richard J. Gaylord's Wolfram Language Fundamentals Part Two" he shows at time 36:45 the following
Where there are two definitions for
w one after that other, then he says that both are entered in the global rules database and then when one is called, the first is called as you see from the screen shot above.
I thought this was strange, because when I tried it on V 13.1, only one definition was entered into the global rules database:
The video is from 2014. So look like it was around version 10 of Mathematica.
My question is: When did this change happen? And is it documented? Notice that different result is obtained than what shows in the video.
ClearAll[w,x] w[x_]:=x^4 w[_]:=RandomReal