Pre-release 7 for Minecraft 1.20 is now available in the Minecraft Launcher. This pre-release adds validation of symbolic links and fixes a bug.

CHANGES

To improve safety, the game will now detect symbolic links used inside world directory.For a detailed explanation, check our help article.

If the target of a symbolic link is not on the user-configured allow-list, the game will not proceed with loading the world
- Note: world directory itself can still be linked
The list of allowed symbolic link targets is stored in file allowed_symlinks.txt in client or server top directory
The file consists of entries (one per line) with following formats allowed:
- Lines starting with # are comments and are ignored
- [type]pattern, where type can be glob, regex or prefix
  - prefix matches start of path with given pattern (so for /test paths /test, /test/ and /test/foo.txt would match)
  - regex matches regular expression against whole path
  - glob uses OS-specific path matching mechanism (for example *.txt would usually match files with txt extension)
  - Note: paths will use OS-specific separators
- pattern, which uses default prefix type

FIXED BUG IN 1.20 PRE-RELEASE 7

MC-257778 - Bamboo Mosaic Slabs and Stairs are not in the #slabs and #stairs block and item tags