I'm asking because I tried to comment line no. 2 and 4 and no effect on the UI. Why there's no effect in UI? I commented line no. 3 and the Home page categories in the landing page disappeared.
In the case of line no. 1, I commented the it and the vivoSlider disappeared.
What is the differnce between the Widget from no. 1 and the widget from line no. 2 and 4?
These all widget are used for placing other content into that widget. So, If you are commenting some widget and some plugins or sliders are not appears because that plugins or widget are placed inside that widget. Generally admin side there is option for where to place content of particular plugin or slider etc.
Hope these will be help you for understanding widget.
Thank you, I will explore with regards to the admin side in line with widgets.
On the other hand, follow-up question. Why there's no effect in UI when I commented line No. 2 and 4?
These are used from Widget plugin. If have any plugin that use your commented line No. 2 and 4 then you may see the changes in UI(not always, bcz widget may push only Js i.e Nop.Plugin.Widgets.GoogleAnalytics).