This is the 13415th most frequent Russian word.
найден
"Found."
Here, 'найден' is used as a past participle describing the state of the treasure being found by someone.
Этот клад был найден археологами.
This treasure was found by archaeologists.
In this instance, 'найден' is used to denote identification of an error during a process.
Ошибка в коде была быстро найдена программистом.
The error in the code was quickly found by the programmer.
Here, 'найдена' represents the successful conclusion of the search for the book, emphasizing the result.