Particularly in the humanities, authors can have multiple classes of
footnotes, including having footnotes of footnotes. The package
bigfoot, among others (see, e.g.,
https://ctan.org/topic/footnote) extends LaTeX’s default
footnote mechanism in many ways, including allowing these two, as in
this example.
\usepackage{bigfoot} % in preamble
\DeclareNewFootnote{Default}
\DeclareNewFootnote{from}[alph] % create note class \footnotefrom{}
...
The third theorem is a partial converse of the
second.\footnotefrom{%
Noted in Wilson.\footnote{Second edition only.}}