Welcome back to the Wefugees Community and thank you for reaching out to us.
As I never came across the AAZUVO either, I tried to make some research. However, all I could find so far was this website explaining some subnational law in the federal state of Baden-Württemberg, if I am not mistaken. Reading the respective section 10 here, did also not make too much sense for me in explaining issuing of your Duldung. The section 10 was referring to general responsibilities and procedures of authorities.
Please check this thread, in which we discussed the different "types" and legal foundations for the issuing of a so-called Duldung before. You may find one of the here mentioned sections (i.e. §60a AufenthG) on your document as well.
I will also link our dear @alla_fka here, as she might be able to give more information on the legal section you were referring to.
However, please don't hesitate to get back to us if you have any further questions or if you want to discuss the linked content.
All the best,