Is it permissible to lend or dispose of books found in mosque libraries, and who has the right to use them?

Endowment (Waqf) is an ongoing charity (sadaqah jariyah), the reward of which reaches the believer after their death. Among these endowments are endowed books. Lending endowed books is permissible if the endower permits it, or if it is customary to do so, provided that the borrowing is documented, the book is preserved, and returned by the specified deadline. However, if the endower stipulated no lending, or if it is not customary to lend them, then it is not permissible to lend them, and they must be read in the mosque. The supervisor of the endowment is bound by the endower's conditions and must not allow access to them by those who will not preserve them.