Each may have private information about its value, clues to which are revealed in the course of the auction.
老师您好，请问to which里的to 我在定语从句里并没有找到适合他的位置啊
这个 to 是与 are revealed 搭配的。如：
The fog cleared and distant hills were revealed to our sight. 雾散了，远处的山峦又展现在我们眼前。（摘自《英汉多功能词典》新编升级版p.1433）
