\AtBeginDvi & \AtEndDvi ¶Synopsis:
\AtBeginDvi{code}
\AtEndDvi{code}
\AtBeginDvi saves, in a box register, code to be executed
at the beginning of the shipout of the first page of the document.
Despite the name, it applies to DVI, PDF, and XDV output. It fills
the shipout/firstpage hook; new code should use that hook
directly.
Similarly, \AtEndDvi (previously available only with the
atenddvi package) is code executed when finalizing the main
output document.