Info-find-node-in-buffer-1 is a compiled Lisp function in `info.el'.

(Info-find-node-in-buffer-1 REGEXP CASE-FOLD)

Find a node or anchor in the current buffer.
REGEXP is a regular expression matching nodes or references. Its first
group should match `Node:' or `Ref:'.
CASE-FOLD t means search for a case-insensitive match.
Value is the position at which a match was found, or nil if not found.