This tax is enforced and collected by VG Media, the German collecting society representing rights of a group of German publishers. https://www.vg-media.de Between 2013 and 2016 Burda was a shareholder of VG Media, which was commissioned to enforce the tax in its name.
The evil thing of this law is, that the publishers are not required to mark their content in machine-readable form as paid content. And a manual selection is infeasible for internet-scale with billions of pages. So a search engine has no means to bypass the paid content and indexing only free content, e.g. like Wikipedia which makes the majority of the internet content. Essentially the "Leistungsschutzrecht" takes the free content hostage to extort money for using the internet, even if you don't use paid content of the publishers (the just 200 publications the VG Media represents).
So while Burda's Cliqz write on their blog "The world needs more search engines" https://www.0x65.dev/blog/2019-12-01/the-world-needs-cliqz-t... they supported a law that made it impossible for many search engines to operate in Germany (and in the EU via the similar EU law "Extra copyright for news sites" (“Link tax”) https://juliareda.eu/eu-copyright-reform/extra-copyright-for... And while today they are not anymore shareholder of the VG Media, they still benefit from the suppressive legal environment they helped to create, as it prevents any new independent competition to enter the search market