A PDF document can have an open action and other additional actions.
Encryption settings are described in section 3.5 (more specifically section 3.5.2) of the PDF Reference 1.7.
A PDF page can have an open and/or close action.
The PDF version is described in the PDF Reference 1.7 p92 (about the PDF Header) and page 139 (the version entry in the Catalog).
Viewer preferences are described in section 3.6.1 and 8.1 of the PDF Reference 1.7 (Table 3.25 on p139-142 and Table 8.1 on p579-581).
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