Function default_allowed_worktree_dirs 

pub fn default_allowed_worktree_dirs(
    environment: &[(OsString, OsString)],
    home: Option<&Path>,
) -> Vec<PathBuf>

What: The tool-cache directories exempt from worktree enforcement on this machine. Vec<PathBuf> is an owned list of owned paths. Why: The set is a property of installed tooling, not of any repository, so it is compiled in rather than configured.

In TS you’d write (pseudocode):

function defaultAllowedWorktreeDirs(environment, home): string[];