Analysis of information sources in references of the Wikipedia article "Scrum (software development)" in English language version.
[...] in practice there proves to be two critical aspects to this role: first as a stakeholder proxy within the development team and second as a project team representative to the overall stakeholder community as a whole.
Ken Schwaber and Jeff Sutherland presented Scrum for the first time at the OOPSLA conference in Austin, Texas, in 1995. [...] In 2001, the first book about Scrum was published. [...] One year later (2002), Ken founded the Scrum Alliance, aiming at providing worldwide Scrum training and certification.
Moving the Scrum Downfield
The activity of continually improving PBIs until they are ready to be worked on is called "refinement."