There are different ways to export event registrations responses but all of them are insufficient or unusable.
By exporting the event registrations we don't have the responses to custom questions. By exporting the Registration responses the excel generate many lines by registrations and finally, when we export the submissions directly from the form we get all responses in responses in one columns, this file is unusable because depending on the answers, the values are added or not in the cell.

The last solution seems to be the most close to what we look but still not ok.
If the contact subscribed to one of those we see in the cell : "Subscribed to XXX: True, ..."
of he subscribed to both we see "Subscribed to XXX: True, Subscribed to YYY: True, ... "

This generates an offset using the text to columns function.

It would be better to use another type of display. If the respondent has not registered, we should add: "Subscribed to XXX: False, " and when there is no answer to a question, "Question: None, "

A better way would be to put each question in columns and the answers below. Each line would be a submission.
Columns 1: Submitted date
Columns 2: Question 1
Columns 3: Question 2
And so on.

This is so basic that we don't understand why this is not already implemented.