The question "What is the company that will organize DrupalCon Europe 2019?" was voted down and then put on hold.
Upon revisiting the existing guidelines, it seems that the question is valid. These are the findings:
1/ The stated reason doesn't not apply
"Questions asking to recommend or find a book, tool, module, theme, distribution, tutorial, or other off-site resource are off-topic for Drupal Answers as they tend to attract opinionated answers and spam. Instead, describe the problem and what has been done so far to solve it."
The question is not asking for a recommendation. Then, there were attempts to find the answer searching on google and on the drupal.org site, but it is not mentioned, because it is implicit, it is expected that you try to find the answer as part of the due diligence.
One could argue that the question is off-topic, but there are reasons to think otherwise which are explained next.
2/ On the What topics can I ask about here? page, it reads:
If your question is about one of the following topics, you're in the right place to ask your question!
3/ On the Ask a question form, it says:
If your question is about code, include the relevant parts.
So, the question can be about something else other than code.