Hello!
I just tried the AppImage and would like to use it portable, but I encountered a problem:
Bail out! Gtk:ERROR:../../../gtk/gtkiconhelper.c:495:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /usr/share/icons/Papirus-Dark/16x16/actions/image-missing.svg: Bildlader-Modul konnte nicht geladen werden: libpixbufloader-svg.so: libpixbufloader-svg.so: Kann die Shared-Object-Datei nicht öffnen: Datei oder Verzeichnis nicht gefunden (gdk-pixbuf-error-quark, 5)
Looks like there is no libpixbufloader-svg.so in /tmp/.mount_paperwOCdiOv/usr/lib/x86_64-linux-gnu/gdk-pixbuf-2.0/2.10.0/loaders.
$ ls -la /tmp/.mount_paperwOCdiOv/usr/lib/x86_64-linux-gnu/gdk-pixbuf-2.0/2.10.0/loaders
insgesamt 222
-rw-r--r-- 1 root root 18552 11. Jan 20:15 libpixbufloader-ani.so
-rw-r--r-- 1 root root 18600 11. Jan 20:15 libpixbufloader-bmp.so
-rw-r--r-- 1 root root 30840 11. Jan 20:15 libpixbufloader-gif.so
-rw-r--r-- 1 root root 14456 11. Jan 20:15 libpixbufloader-icns.so
-rw-r--r-- 1 root root 22736 11. Jan 20:15 libpixbufloader-ico.so
-rw-r--r-- 1 root root 18640 11. Jan 20:15 libpixbufloader-pnm.so
-rw-r--r-- 1 root root 14480 11. Jan 20:15 libpixbufloader-qtif.so
-rw-r--r-- 1 root root 18568 11. Jan 20:15 libpixbufloader-tga.so
-rw-r--r-- 1 root root 22664 11. Jan 20:15 libpixbufloader-tiff.so
-rw-r--r-- 1 root root 14456 11. Jan 20:15 libpixbufloader-xbm.so
-rw-r--r-- 1 root root 34936 11. Jan 20:15 libpixbufloader-xpm.so
Since some modern themes rely on SVG-Images, could this please be added?
Thank you!
done 
. You can re-download the appimage, libpixbufloader-svg.so has been added.