I made a patch for a plugin of Okular to view PDF with MuPDF, and uploaded a package to build and install the plugin in AUR.
https://aur.archlinux.org/packages/okul … end-mupdf/
Although Some source codes to use MuPDF as a plugin of Okular have been included in KDE svn a long time ago, official releases of KDE have never contained them since they exist in playground not in trunk.
Moreover, it cannot be compiled with recent MuPDF.
My patch makes it possible that the plugin can be compiled and linked with recent release of MuPDF.
I've tested only viewing functions, and I'm not sure that the printing functions work since I don't have a printer.
Anyway, MuPDF is amazingly fast!