Problem is likely that our version of HTML Tidy is outdated. Or we need to default to using html5lib for syntax checking.

HTML5 is the latest version of the Hypertext Markup Language. HTML is a standard programming language for creating websites and web applications. HTML5 has become the most widely used version and is ...

In the older version of HTML, we need to write a long like to declare DOCTYPE because HTML is SGML(Standard Generalized Markup Language) based so its need a DTD (document type definition).

There is an error while package project to HTML5： UATHelper: Packaging (HTML5): XXX: -o D:\resource\UE\src\UnrealEngine-4.27-html5_dev\Engine\Binaries\HTML5\UE4Game ...