TypoScript Template Render Fix - Hotfix if some TYPO3 plugins render unwanted HTML and you need a way to replace this without changing the plugin

page.typoscript

# page = PAGE
# page.10 = FLUIDTEMPLATE
# page.10 {
#    # TYPO3 page template and all content rendered here, containing some unwanted markup
# }
   
### Template Render Fix
page.10 {
  stdWrap.replacement {
    ### Replace legacy Values
    10 {
      search = Old Name
      replace = New Name
    }
    ### Force HTTP to HTTPS
    20 {
      search = http://example.com
      replace = https://example.com
    }
    ### Force CDN usage
    30 {
      search = "/fileadmin/
      replace = "https://cdn.example.com/fileadmin/
    }
  }
}

TypoScript Replacement supports RegEx as well: https://docs.typo3.org/m/typo3/reference-typoscript/10.4/en-us/Functions/Replacement.html

There is an extension to replace strings in the output document as well: https://extensions.typo3.org/extension/replacer/

Example Code: https://docs.typo3.org/p/jweiland/replacer/1.5/en-us/Configuration/Index.html#basic-search-and-replace