From the official website (https://pympress.xyz ):
Pympress is a little PDF reader written in Python using Poppler for PDF rendering and GTK+ for the GUI.
It is designed to be a dual-screen reader used for presentations and public talks, with two displays: the Content window for a projector, and the Presenter window for your laptop. It is portable and has been tested on various Mac, Windows and Linux systems. More Info »
It comes with many great features:
supports embedded videos
text annotations displayed in the presenter window
natively supports beamer’s notes on second screen!
Pympress is a free software, distributed under the terms of the GPL license (version 2 or, at your option, any later version).