In the foreign Languages Bookstore are to be found books in various languages.
这是一个倒装句。恢复正常语序为:
Books in various languages are to be found in the Foreign Language Bookstore.
这是be to do结构表示将来时间。这种结构表示安排、计划、命令、注定会在将来发生的事件。你可以近似地理解为will do. 即are to be found大约等于will be found.