> Well, there's specifying a second argument to the FD macro > which causes the footnote counter to get reset at each > first-level heading, but that appears to be just as > undocumented.
>From HP's "Text Formatting User's Guide" (ca. 1991): If the second argument is specified, automatically-numbered footnotes begin again with 1 whenever a first-level heading is encountered. This is most useful with the "section-page" page numbering scheme. As an example, the input line .FD "" 1 maintains the default formatting style and causes footnotes to be numbered afresh after each first-level heading in a document.