AppImage not working on Ubuntu 25.10; libfuse problems

[dandrake]

I had trouble running UHK Agent on Ubuntu 25.10 -- I first got this:

%` ./UHK.Agent-8.0.1-linux-x86_64.AppImage
dlopen(): error loading libfuse.so.2

AppImages require FUSE to run.
You might still be able to extract the contents of this AppImage
if you run it with the --appimage-extract option.
See https://github.com/AppImage/AppImageKit/wiki/FUSE
for more information

It looks like it needs libfuse2; I have libfuse3 installed. (See this issue). I installed libfuse2t64 and tried again, but I got:

% ./UHK.Agent-8.0.1-linux-x86_64.AppImage
The setuid sandbox is not running as root. Common causes:
  * An unprivileged process using ptrace on it, like a debugger.
  * A parent process set prctl(PR_SET_NO_NEW_PRIVS, ...)
Failed to move to new namespace: PID namespaces supported, Network namespace supported, but failed: errno = Operation not permitted
[663429:1225/055730.130874:FATAL:content/browser/zygote_host/zygote_host_impl_linux.cc:211] Check failed: . : Invalid argument (22)
zsh: trace trap (core dumped)  ./UHK.Agent-8.0.1-linux-x86_64.AppImage

I went down a bit of a rabbit hole from there; I tried running it with sudo. I also tried using the --appimage-extract thing suggested initially. That in turn complained about root ownership and 4755 permissions, but even with that it didn't work.

In the end, I got it to run with --no-sandbox.

It would be useful if there was some documentation on this -- maybe say something in the README?