Inside Emacs at  the infopage for Emacs, the search  term "two column"
finds   no   result,  the   search   term   "column"  finds   in   the
"Info Virtual Index" the result:

  . 2C-two-columns [Command Index]: Two-Column.

Steps to reproduce

  . start "emacs -Q"
  . open Emacs's infopage by "F1 i" and navigating to entry for Emacs
  . search index using "I" and type "two column"
  . echo area says "No 'two column' in index"

Expected result finds

  . 2C-two-columns [Command Index]: Two-Column.

-- 
vl					     GNU Emacs 27.2 NetBSD 9.3