Hi,
seconding @pfeigl here:
we also moved a system of ours from .NET Framework -> .NET6 recently and experienced some changes in header-properties behaviour, in this case Content-Length not being filled anymore by the FileStreamResultExecutor of .net6.0 even though the Stream which is passed into the FileStreamResult has a length defined.
That field had been filled before with .Net Framework !
In the end we filled Content-Length in these special cases in our WebApi within our code to ensure identical behaviour for our clients.
I'm very convinced that ProGet's behaviour regarding Last-Modified was different before ProGet 2022 !
So, while I understand your statement "The platform is what's responsible for reading/responding to cached/head requests." I would still very much appreciate Inedo working around this behaviour in the code or at least documenting this as breaking change.
(The former I would prefer obviously ;-) because it would help our build process based on Jenkins as mentioned above.)