Comment # 1 on bug 1045569 from Wolfgang Bauer

This is a conscious upstream change/design decision in the breeze widget style.

You can enable the arrow buttons via its settings though, "Configure
Desktop"->Application Style->Widget Style->Configure... (or run
breeze5-settings).

Or switch to a different widget style if you prefer.

Personally I don't like that change either, but I'm not sure we should deviate
in our default settings from upstream.

GNOME/GTK's defaults don't have the arrow buttons either btw, and I think that
was one reason for this change.