Symlink Check

Official patch notes for version 1.20-pre7 contained an important mention:

To improve security, the game will now detect symbolic links inside the worlds folder. See our help article for details.

As explained in the reference material, attacks using symbolic links can lead to irreversible loss of game data. However, the mechanism for detecting dangerous links and the corresponding warning have not been officially ported to older Minecraft versions - this is precisely why this modification was created.

When you try to open a world with symbolic links, a special warning window will appear. The only exceptions are links that are added to the whitelist in the allowed_symlinks.txt file.