TYPO3 Core

Currently the behaviour of #91499 is different depending on the variant of page.includeCSS* / includeJS* used.

See following table for an overview:

	data.data-xxx / data.foo	data-xxx / foo
--------------	--------------------------	----------------
CSS	Exception	+
CSSLibs	Exception	+
JS	+	-
JSFooter	+	-
JSLibs	Exception	+
JSFooterlibs	Exception	+

Exception means: array to string exception as there is a string expected when an array gets delivered
+: working
-: not working

When using page.includeJS / page.includeJSFooter you have to add additional attributes as data-array.
But when using includeCSS or one of the libs-variants you must not use data-array but deliver additional attributes as key-value pairs directly.

This issue is opened as FollowUp of #100954 which was already marked ad resolved.

Following ideas were already collected:

• "quickfix" for v12 to use both variants data.foo and foo side by side in all cases
• add a "new" param to includeCSS*/includeJS* -> additionalAttributes to overtake the functionality
• mark data. and the plain usage of data-main deprecated in v13 and remove in v14

reasons for change from data. to additionalAttributes.:

• it is not only about data-attributes
• data in TypoScript is in some way related to getText
• additionalAttributes is already used as wording in fluid for the same topic

reasons for change from key/value to additionalAttributes.:

• separate parameters with defined functions from those with just free behaviour
• easier to handle with specified array collecting all additional attributes, see includeJS/includeJSFooter in \TYPO3\CMS\Frontend\Http\RequestHandler