This is the official manual for the latest Org-mode release.
:eval header argument can be used to limit the evaluation of
specific code blocks. The
:eval header argument can be useful for
protecting against the evaluation of dangerous code blocks or to ensure that
evaluation will require a query regardless of the value of the
org-confirm-babel-evaluate variable. The possible values of
:eval and their effects are shown below.
never or no
never-export or no-export
If this header argument is not set then evaluation is determined by the value
org-confirm-babel-evaluate variable see Code evaluation security.