Apvlv is a PDF Viewer based on GTK and poppler which uses Vi-like
keybindings.  For example, <Ctrl-f> to forward page, <Ctrl-b>
to previous page, 'k','j','h', and 'l' to scroll a page up, down,
left or right.  Typing '50' and <Ctrl-f> will go forward 50 pages;
typing '30' and <Ctrl-b> will go previous 30 pages.  Apvlv can support
viewing a directory as contents of a pdf document. Press 'k' or 'j'
to move selected up or down, 'h' or 'l' to collapse or expand a dir,
and pressing 't' will open the selected document in a new tab.

This SlackBuild disables UMD file support.