Log Message:
Import tex-placeins-plain-2.0 as print/tex-placeins-plain.

This TeX file provides various mechanisms (for plain TeX and close
relatives) to let insertions (footnotes, topins, pageins, etc.) float
within their appropriate section, but to prevent them from intruding
into the following section, even when sections do not normally begin a
new page.  (If your sections normally begin a new page, just use
\supereject to flush out insertions.)