It seems that PrintScreen is now bound to Gnome Settings Daemon, which is used to take screenshots instead of gnome-screenshot. Keyboard settings (in Gnome settings) still has a screenshot shortcuts section in the keyboard shortcut settings, but those too now only trigger Gnome Settings Daemon’s screenshot feature, not gnome-screenshot.

What’s worse, disabling those shortcuts does not allow for remapping PrintScreen back to gnome-screenshot using a custom shortcut, as pressing PrintScreen in the shortcut selector window still just triggers the GSD ’blink’ instead of registering PrintScreen as the new shortcut key for the custom command. Only the screenshot section’s pre-defined actions allow for PrintScreen to be grabbed. (At least that’s what it does here.)

When the screenshot shortcuts are disabled, nothing is apparently saved anywhere despite the blink effect. The ”Save a screenshot to Pictures” shortcut has to be defined for the screenshots to actually get saved, and then they will be unconditionally saved to $XDG_PICTURES_DIR: https://bugzilla.gnome.org/show_bug.cgi?id=699642