PccArticlesMapper::toArticleData is very opaque

[chx]

This method casts an object from a dependency into an array

And while the object in question currently only contains public properties it still requires cross-project referencing to figure this out -- and since the object has the AllowDynamicProperties attribute, it's really anyone's guess what this method returns.

It would be much better to spell it out like

return [
  'id' => $article->id,
  'title' => $article->title,
]

and so forth.

Alternatively, since I doubt there are any BC concerns yet just remove this method completely and inline it into toArticlesList? As far as I can see there's no other use of it and so why expose it then?