_D6tagion7betterC5utils6RBTree__T7RBTreeTTPSQBqQBm5hibon5HiBON6HiBONT6MemberZQBs4NILLSQDgQDcQCxQCu__TQCqTQClZQCy4Node

Undocumented in source but is binding to C. You might be able to learn more by searching the web for its name.
extern (C)
HiBONT_RBTreeT _D6tagion7betterC5utils6RBTree__T7RBTreeTTPSQBqQBm5hibon5HiBON6HiBONT6MemberZQBs4NILLSQDgQDcQCxQCu__TQCqTQClZQCy4Node;

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