Okular also pulls in a sizeable part of KDE as dependencies: Depends: kinit, kio, libc6 (>= 2.33), libfreetype6 (>= 2.2.1), libjpeg62-turbo (>= 1.3.1), libkf5a

Okular also pulls in a sizeable part of KDE as dependencies: Depends: kinit, kio, libc6 (>= 2.33), libfreetype6 (>= 2.2.1), libjpeg62-turbo (>= 1.3.1), libkf5activities5 (>= 5.68.0~), libkf5archive5 (>= 5.68.0~), libkf5bookmarks5 (>= 5.68.0~), libkf5codecs5 (>= 4.96.0), libkf5completion5 (>= 5.68.0~), libkf5configcore5 (>= 5.68.0~), libkf5configgui5 (>= 5.68.0~), libkf5configwidgets5 (>= 5.83.0), libkf5coreaddons5 (>= 5.68.0~), libkf5crash5 (>= 5.68.0~), libkf5i18n5 (>= 5.68.0~), libkf5itemviews5 (>= 4.96.0), libkf5jobwidgets5 (>= 4.96.0), libkf5kexiv2-15.0.0 (>= 5.68.0~), libkf5kiocore5 (>= 5.69.0), libkf5kiowidgets5 (>= 5.69.0), libkf5parts5 (>= 5.68.0~), libkf5pty5 (>= 5.68.0~), libkf5purpose-bin, libkf5purpose5 (>= 5.68.0~), libkf5service-bin, libkf5service5 (>= 4.96.0), libkf5textwidgets5 (>= 5.68.0~), libkf5wallet-bin, libkf5wallet5 (>= 5.68.0~), libkf5widgetsaddons5 (>= 5.77.0), libkf5windowsystem5 (>= 5.68.0~), libkf5xmlgui5 (>= 5.80.0), libokular5core9 (= 4:21.12.3-2), libphonon4qt5-4 (>= 4:4.8.0), libpoppler-qt5-1 (>= 21.11.0), libqmobipocket2 (>= 4:17.08~), libqt5core5a (>= 5.15.1), libqt5dbus5 (>= 5.14.1), libqt5gui5 (>= 5.14.1) | libqt5gui5-gles (>= 5.14.1), libqt5printsupport5 (>= 5.13.0~), libqt5texttospeech5 (>= 5.12.0~), libqt5widgets5 (>= 5.15.1), libqt5xml5 (>= 5.13.0~), libspectre1 (>= 0.2.3), libstdc++6 (>= 11), phonon4qt5, zlib1g (>= 1:1.1.4) Compare this to mupdf: Depends: freeglut3 (>= 2.8.1), libc6 (>= 2.33), libfreetype6 (>= 2.6), libgl1, libgumbo1 (>= 0.9.2), libharfbuzz0b (>= 0.9.11), libjbig2dec0 (>= 0.19), libjpeg62-turbo (>= 1.3.1), libmujs1 (>= 1.0.7), libopenjp2-7 (>= 2.0.0), libssl1.1 (>= 1.1.0), libx11-6, libxext6, zlib1g (>= 1:1.2.0) If you're already using KDE Okular is a natural choice. If you're not there are better alternatives, e.g. Atril for Mate-users, Evince for Gnome users and, yes, mupdf for those who do not use any "desktop environment". Those who use older hardware (like me) appreciate the nimbleness of tools like mupdf. It also fits in perfectly when using a tiling window manager (Xmonad etc) as it does not have any UI elements getting in the way, only showing what you're actually interested in. It supports (according to the man page) PDF, XPS, EPUB, XHTML, CBZ, and various image formats such as PNG, JPEG, GIF, and TIFF. This is akin to vi vs VS-Code, to each his own I'd say.