public String getUserByDistinguishedName(X500Principal x500User) {
		synchronized (repositoryMgr) {
			UserEntry entry = dnLookupMap.get(x500User);
			return entry != null ? entry.username : null;
		}
	}
Returns the username associated with the specified distinguished name
@param x500User a user's X500 distinguished name
@return username or null if not found
Ghidra/Features/GhidraServer/src/main/java/ghidra/server/UserManager.java