in \lib\pkp\locale\en_US\common.xml contain variables 
but they are not displayed on the site. perhaps they need to be prescribed elsewhere or add somewhere else? (ojs 3.1)
Sorry, this is my mistake. 
I immediately went to change the variables. But the variables are displayed as ## variable ##. And I decided to check in the menu editor, and I saw exactly these points there 
maybe this happened when upgrading from 3.0 to 3.1
