I’m pretty used to opening contours by selecting a segment, then using Opt+Delete to delete the segment and leave open points on either side. This helps me connect other points to that opened contour.
Halfway through making this post as a question, I figured out the answers by experimenting. I’m posting in case someone else searches this. Current shortcuts:
Shift+Deletedeletes selected segments and leaves an open contour.Opt+Deletedeletes selected segments and closes those contours, on all masters.Shift+Opt+Deletedeletes selected segments and leaves an open contour, on all masters.
The old shortcut is described in the Handbook, and that seems to not yet be updated:
As a visual, here’s what Opt+Delete now does. It deletes selected segments on all masters, but also keep those contours closed:


