This is the Quick Origin add-on created by Ishidourou in 2014, modified to work with Blender 2.80. Once enabled in the Preferences / Add-ons you can select a single or multiple vertices, edges, faces in Edit Mode then press the button named "Set Origin" that can be found in the "Sidebar" panel (press "N" key) inside the tab on the right named "Quick Origin".
Changed version to 1.1. Renamed add-on file to "quickorigin.py".
References to the original Author of this add-on:
Name: Ishidourou Video: http://youtu.be/ZD3L-xMEzcc Web: http://stonefield.cocolog-nifty.com/higurashi/2014/09/quick-origin-fd.html Download: http://ishidourou.o.oo7.jp/scripts/quickorigin10.py