Crashes when "tor-browser_en-US" folder is not empty

[Fabs37]

Hey people,

on my machine (Fedora 40, Tor Browser 13.5.1 (based on Mozilla Firefox 115.13.0esr) via torbrowser-launcher v0.3.7) Tor Browser is installed at ~/.local/share/torbrowser/tbb/x86_64/tor-browser.

The folder ~/.local/share/torbrowser/tbb/x86_64/tor-browser_en-US didn't exist, until an external application (in my case, KeePass XC's browser integration) created it by writing their config file (more precisely, ~/.local/share/torbrowser/tbb/x86_64/tor-browser_en-US/Browser/TorBrowser/Data/Browser/.mozilla/native-messaging-hosts/org.keepassxc.keepassxc_browser.json into it.

The file had no effect there (i.e. KPXC's browser integration didn't work) but to crash torbrowser-launcher when I tried to restart it:

$ torbrowser-launcher 
Tor Browser Launcher
By Micah Lee & Tor Project, licensed under MIT
version 0.3.7
https://gitlab.torproject.org/tpo/applications/torbrowser-launcher/
Traceback (most recent call last):
  File "/usr/bin/torbrowser-launcher", line 31, in <module>
    torbrowser_launcher.main()
  File "/usr/lib/python3.12/site-packages/torbrowser_launcher/__init__.py", line 81, in main
    common = Common(tor_browser_launcher_version)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/torbrowser_launcher/common.py", line 53, in __init__
    self.torbrowser12_rename_old_tbb()
  File "/usr/lib/python3.12/site-packages/torbrowser_launcher/common.py", line 176, in torbrowser12_rename_old_tbb
    os.rename(abs_filename, self.paths["tbb"]["dir_tbb"])
OSError: [Errno 39] Directory not empty: '/home/fab/.local/share/torbrowser/tbb/x86_64/tor-browser_en-US' -> '/home/fab/.local/share/torbrowser/tbb/x86_64/tor-browser'

I wonder whether it tried to merge the tor-browser_en-US folder's content into tor-browser. Because that is what I did then and after that, both Tor Browser and KPXC's browser integration worked without problems.

This issue is a duplicate of keepassxreboot/keepassxc-browser#2294 since the KeePass devs said it's not their bug.