emacs-devel archive search with no results --- index incomplete?

[Harald Kirsch]

Hi all,

searching on https://lists.gnu.org/archive/html/emacs-devel/ for emails
one of which contains

  An Eglot supplement which shows a call or type hierarchy

Searching for the word

  supplement

and selecting "in chronological order" the most recent result email is
from 2021. Clearly the archive contains the relevant Email sent Dec. 11
19:4+00 with subject

  eglot-cthier.el --- show call and type hierarchy with Eglot

Is there some search trick I am missing or is the index of the search
engine just incomplete?

Harald