SUMMARY Okular like usual document readers is not that good at rendering epub files, currently Foliate is the best linux app in true and usable rendering of epub files because of doing it with webkit and epub.js library. Currently epub files with size of + 10 MB are impossible to load in okular, and will make the app freeze and need to kill, very light and simple epubs also are not easy and pleasant to read in okular. As qt5-webengine is a mandatory dependency of Plasma , okular needs a epub backend based on webengine and epub.js just like what foliate does in this way. STEPS TO REPRODUCE 1. Open a epub in okular 2. You will never have a good experience when reading it on okular 3. Nothing will rendered properly and as it should be OBSERVED RESULT EXPECTED RESULT SOFTWARE/OS VERSIONS Linux : Arch Linux KDE Plasma Version: 5.22.3 KDE Frameworks Version: 5.83 Qt Version: 5.15.2 KDE ADDITIONAL INFORMATION