         ext0 = filename_extension_notilde(path)?.toLowerCase()
         ext = filename_extension(path)?.toLowerCase()
         if ext0 != ext
-            @setState(error: "Please rename the archive file to not end in a tilde.")
+            @setState(error: <span>Please rename the archive file to not end in a tilde.</span>)
             return
 
         if not COMMANDS[ext]?.list?

            err_on_exit: true
            cb         : (err, output) =>
                @setState
                    error    : if err then <pre>{err}</pre>
                    contents : output?.stdout
                    type     : ext


                    timeout    : 120
                    cb         : (err, _output) =>
                        output = _output
                        if err
                            err = err.toString()  # it's an Exception object otherwise -- see https://github.com/sagemathinc/cocalc/issues/3280
                        cb(err)
        ], (err) =>
            @setState
                error          : if err then <pre>"${err}"</pre>
                extract_output : output?.stdout
                loading        : false
        )
