Clarification of the open question :

How can we use intents from the Wikidata items in this project (with the scope of the publication in mind) ? How can the intents be notated in these Wikidata items?

I was guessing one can start with the UpdateMath ...

Ok, this is a start, when this is set up and generated with the UpdateMath file, the only difficulity i see is to filter the correct Wikipages from the output (depending on the content of Database), there can be lots of items processed by this scripts). But this should be possible on a local instance with MediaWiki etc which only has the most necessary Wikipages.

In T312530#8531088, @Reedy wrote:

Please stop closing tasks as invalid when they are duplicates. Use the "Close as Duplicate" feature.

closed, as this is a duplicate of "T310211 Deliver visible MathML to the browser"

Thanks for adding the hints, here some questions and remarks (to @Physikerwelt ) to refine the essence of the tasks:

This is a duplicate of "T310211 Deliver visible MathML to the browser"

Since chem and inline are supported, this can be considered done. If experimental types should be supported once a while, i suggest creating another task for this.

@Physikerwelt could you have a look at this and check if everything is correct, something is missing and edit where necessary ?

After correspondence with Marcel Bolton and rechecking the grammar without the modifications, all testcases have been running.

Hey @dom_walden thanks for the patch for AllTests. I had a check with the current WIP state (https://gerrit.wikimedia.org/r/830178), and I applied the dataProvider from the patch instead of loop, great suggestion.
I could fix all cases of the tests locally in WIP state (except the unicode testcase, skipped atm) through debugging the PHP grammar.