Interesting, did not now about the amtliche Fassung. But the full archive with the amtliche Fassung is also published online for free, starting from 1949: https://www.bgbl.de/xaver/bgbl/start.xav

They also mention it on the gesetze-im-internet website: https://www.gesetze-im-internet.de/hinweise.html

It seems that the Austrian way is much better though.