saas-one/frontend/saas-web/ext/packages/modern-locale/overrides/zh_CN/window/MessageBox.js

Ext.define('Ext.locale.zh_CN.window.MessageBox', {
    override: 'Ext.window.MessageBox',

    buttonText: {
        ok: 'OK',
        yes: '是',
        no: '否',
        cancel: '取消'
    }
});