Timeline: external Wiki content automatically reverts to `eng.wikipedia...`

When using the Additional content option in Timeline (which is awesome, by the way :) ), wikipedia-content added in other languages than English automatically reverts back to the English version  (in my particulr case: https://en.wikipedia.org/wiki/Upload-Filter (which doesn't exist)).

In addition, it would be great if html anchors could be referenced as well - atm, only the base wikipedia article can be linked to, but in my case, it would have been amazing to actually link to https://de.wikipedia.org/wiki/Upload-Filter#Geplante_Rechts%C3%A4nderung...

Example:

• https://openlab.blogs.uni-hamburg.de/timeline-development-of-oer-in-germ...
• See slide: 2018 July 05 "Reform des Urheberrechts in Europa" (one of the last ones)

To reproduce:

1. Make use of additional content part with non-English wikipedia entry
2. 
3. Save
4. Open Timeline in frontend
5. Click on headline, see if content link works with intended non-English language wikipedia entry
6.