Motivation for this change

This depends on #1829, hence the draft status

@holgerthies @IshiguroYoshihiro @yosakaon

can you check and tell if it is ok?

Checklist

• added corresponding entries in CHANGELOG_UNRELEASED.md

• added corresponding documentation in the headers

Reference: How to document

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As a rule of thumb:

• PRs with several commits that make sense individually and that
  all compile are preferentially merged into master.
• PRs with disorganized commits are very likely to be squash-rebased.

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• Read this Checklist
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