Is there a portable version of KDE's Dolphin file manager, i.e. a version that can be stored on a USB stick, for example, and run on arbitrary Linux operating systems?
So far the only thing I could find was a 3-year-old AppImage in a non-official GitHub repo.
Does anybody know where to get an official, up-to-date portable version, or where to find potential instructions on how to make Dolphin portable?
As far as I know, there is no official dolphin AppImage but you can create one using appimage-builder. Check https://appimage-builder.readthedocs.io/en/latest/intro/examples.html#qt-kde-application-kcalc it contains a recipe for a KCalc which can be modified to bundle Dolphin.
Also, you should consider requesting this to the Dolphin creators.