Subject: bug#61375: HTML+ <input checked> not highlighted

From: Eli Zaretskii <[email-masked]>
Date: Thu, 09 Feb 2023 08:45:30 +0200

> From: Dan Jacobson <[email-masked]>
> Date: Thu, 09 Feb 2023 09:45:57 +0800
> 
> In HTML+ mode the word "type" is highlighted, but not the word
> "checked", in
> <input type="checkbox" checked>
> emacs-version "28.2"

What is "HTML+ mode", please? is it part of Emacs?