When rendering HTML5 output,
<script> tags do not the additional attribute
anymore as it is considered optional, and if none given, modern browsers fall back to this type
See the official W3C definition here: https://www.w3.org/TR/html52/semantics-scripting.html#element-attrdef-script-type
For this reason, all of TYPO3's Backend (which is rendering HTML5) and Installer do not include
this optional attribute in
<script> tags anymore.
For TYPO3 Frontend rendering, the attribute is omitted when having no doctype or HTML5 as doctype
configured (via TypoScript
config.doctype = html5). This leads to a minimal smaller
HTML document submitted to the client.
For any XHTML or HTML4-based website, the attribute is still added.
TYPO3's Frontend rendering does not render
<script> tags when
rendering a HTML5 output, unless explicitly specified.
Any TYPO3 installation running a HTML5-based frontend output.
As all modern browsers do not need this tag, and the specification says it's optional, there is no migration needed at all.
If still requested by a specific project, it can be added via: