Invalid xml namespaces on div elements

[benjaminkott]

Bug Report

Prerequisites

• Can you reproduce the problem on TYPO3 v8.7 LTS
• Can you reproduce the problem on TYPO3 v9.5 LTS
• Did you perform a cursory search to see if your bug or feature is already reported?

Description

HTML Templates contain fluid namespace definitions on unsupported elements.

<div 
    xmlns:f="http://www.w3.org/1999/html" 
    xmlns:blog="http://typo3.org/ns/T3G/AgencyPack/Blog/ViewHelpers"
>
    ...
</div>

Steps to Reproduce

1. Install Blog Extension
2. Include Tempalte
3. Insert "Blog: List of posts" plugin
4. Check frontend markup

Expected behavior: [What you expected to happen]

Namespaces for fluid viewhelper resolving should not be rendered in frontend

Actual behavior: [What actually happened]

Invalid namespaces are rendered in the frontend.

Versions

All versions