One of the common things in most of the applications build on SharePoint is to have a custom master page. The custom master page is build mainly to apply the branding of the company/ product and to have a good responsive design.But since the formation of PnP community and SharePoint 2016 announcement things are going to be different . SharePoint 2016 is speculated to be natively responsive, so if you were creating custom master page just so that your company branded site should be responsive then its time to not go that way.But wait we are still in SharePoint 2013 now what ? Couple of weeks back office PnP team announced Responsive UI Package for SharePoint on-premises (2013 and 2016). Now after this announcement if you are still making custom master pages and not using design manager to create branding theme for your site , it’s a crime!
See how it works in this video