The first extension is the newly created action set, which defines the menu, toolbar path, tool tip, icon, and the actions to call when it is selected.

第一个扩展是新建的操作集，它定义了菜单、工具栏路径、工具提示、图标以及被选中后希望调用的操作。

youdao

Clicking off the main menu bar allows you to follow the path of da Vinci's work, from his earliest sketches to famous paintings and his scientific musings.

BBC: 8bitpeoples