official [NO LONGER WORKS!]
https://forums.alliedmods.net/showthread.php?t=93600
https://forums.alliedmods.net/showpost.php?p=1874602&postcount=1123
https://github.com/ivailosp/l4dtoolz/releases

unofficial by ivailosp [NO LONGER WORKS!]
https://forums.alliedmods.net/showpost.php?p=2682998&postcount=1427
https://forums.alliedmods.net/showpost.php?p=1984946&postcount=1211?p=1984946&postcount=1211

unofficial by maks (for L4D1 Linux)
https://forums.alliedmods.net/showpost.php?p=2464842&postcount=1327

unofficial by SirPlease (for L4D2 Linux)
https://forums.alliedmods.net/showpost.php?p=2711810&postcount=1436
https://github.com/SirPlease/L4D2-Competitive-Rework/blob/master/addons/l4dtoolz/l4dtoolz_mm.so

unofficial by Spirit_12 (for L4D1/L4D2 Windows) [NO LONGER WORKS FOR L4D2 LINUX!]
https://forums.alliedmods.net/showthread.php?p=2532119#post2532119
https://forums.alliedmods.net/showpost.php?p=2532584&postcount=1345