Keynote Remote is described as 'Your show. Your way—Keep the pace of your presentation flowing smoothly with the Presenter Display feature. While your presentation appears on the main display for your audience, you can see the current and next slides, your slide notes, a clock, and a timer on a second display' and is an app in the office & productivity category. There are three alternatives to Keynote Remote for iPhone, Linux, Mac, Windows and Electron / Atom Shell. The best alternative is Rowmote. It's not free, so if you're looking for a free alternative, you could try PhonePresenter.