Huh, I didn't know that. But it seems incomplete, at least for Baden-Württemberg. Not sure if that's a bug, an outage, or if they didn't submit all the data. On unternehmensregister.de, you can usually view lots and lots of information, including annual reports (with increasing detail, depending on company size).

As far as I understand it, on unternehmensregister.de, you only have to pay for access to files (including annual reports) of small companies that make use of the § 326 Abs. 2 HGB exception: https://www.buzer.de/326_HGB.htm And maybe for formally authenticated copies? Everything else should be free of charge.