texinfo-update-menu-same-level-regexps

texinfo-update-menu-same-level-regexps is a variable defined in `texnfo-upd.el'.
Its value is

((1 . "top[ 	]+")
 (2 concat "\\(^@\\)\\(" texinfo-chapter-level-regexp "\\)\\>[ 	]*")
 (3 concat "\\(^@\\)\\(" texinfo-section-level-regexp "\\)\\>[ 	]*")
 (4 concat "\\(^@\\)\\(" texinfo-subsection-level-regexp "\\)\\>[ 	]+")
 (5 concat "\\(^@\\)\\(" texinfo-subsubsection-level-regexp "\\)\\>[ 	]+"))

Documentation:
Regexps for searching for same level sections in a Texinfo file.
The keys are strings specifying the general hierarchical level in the
document; the values are regular expressions.