placeins-plain – Insertions that keep their place

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.)