$ lua -v -e "print(os.date('%l'))"
Lua 5.2.2  Copyright (C) 1994-2013 Lua.org, PUC-Rio
lua: (command line):1: bad argument #1 to 'date' (invalid conversion specifier '%l')
stack traceback:
    [C]: in function 'date'
    (command line):1: in main chunk
    [C]: in 
その場合、どこにバグ レポートを提出すればよいですか?