MuPDF viewer is an app for reading PDF, XPS, CBZ, and unprotected EPUB documents.
This is a slim version of the MuPDF app, which focuses on reading only. It does not support editing annotations or filling out forms.
Tapping on the left and right side of the screen will flip to the previous and next pages. Tapping in the middle of the screen will bring up or hide the tool bars.
The link button in the tool bar will toggle highlighting hyperlinks. When the links are highlighted they are also active and tappable. You can pinch to zoom in and out. When zoomed in, tapping will scroll to advance to the next screenful of content.
The toolbar also has a search button, and possibly a table of contents button.
The scrubber at the bottom of the screen will let you quickly go to any place in the document.
With the "Overview" system button, you can go back to the file chooser and open multiple documents at once.