UPDATE: The Bundestag has amended its announcement about the passing of reform of the Youth Protection Act to remove mention of loot boxes.
It appears the Bundestag made a mistake with its own announcement of the legal reform. The announcement, which can be viewed on the Bundestag's website, no longer includes the line: "It is also planned to deactivate cost traps such as 'loot boxes' by default."
The amendment does stipulate that age ratings will be expanded to include descriptors for various problematic mechanics, including "cost traps". The idea here is to indicate risk if it was not taken into account in the age classification.
However, there is currently no indication that video games with loot boxes will be rated 18+.
The headline of this article has been changed to reflect the change in the Bundestag's announcement.