If you install the Tor Browser‘s launcher via sudo dnf install torbrowser-launcher and then installed the browser via the launcher on a freshly installed Fedora 39 KDE Plasma Spin system, you may encounter this problem. In this scenario, the browser can not be launched and CLI says (with --verbose):
XPCOMGlueLoad error for file /home/$USER/.local/share/torbrowser/tbb/x86_64/tor-browser/Browser/libxul.so:
libdbus-glib-1.so.2: cannot open shared object file: No such file or directory
Couldn't load XPCOM.
The solution is easy as follows.
Installing Missing Dependency
Install a package named dbus-glib. sudo dnf install dbus-glib
Retry to launch the browser now.