Hi Christian,
You are right in that observational studies are currently not regulated with respect to the validity of the analysis software. However, that does not stop regulators from asking for artifacts supporting said validity (and recently they do this more and more). The document I drafted is intended to be such an artifact, and in absence of regulations specific to observational studies I propose we take the regulations specific to RCTs as a starting point. Also, in general it is good to think about software validity in a more structured way, even outside of any regulatory requirements.
You are also right that Part 11 does not precisely apply to observational studies, and this is apparent everywhere in the document where it says
The Methods Library is not intended to create, maintain, modify or delete Part 11 relevant records but to perform population-level effect estimation, including relevant output necessary for understanding the estimate and the estimation characteristics.
Quite honestly I simply copied this part from this document by the R foundation. We do create some records, mostly meta-data about the execution of the study and the actual results, and the document therefore simply checks whether we would meet regulatory requirements if those included Part 11.