Ok so, I think I got it working by just adding a "prefix" to the URL, i.e. the json data is the same as shown in my previous message, but the URL now changed to:
Of course that is just a dummy prefix, but the point being, it appears one must pass a prefix.
The response will give an output like this:
[{"AcquireByHash":false,"Architectures":["all","amd64"],"ButAutomaticUpgrades":"","Distribution":"bookworm","Label":"","NotAutomatic":"","Origin":"","Path":"filesystem:FPBX17-qa-web:fpbx17/bookworm","Prefix":"my-prefix","SkipContents":false,"SourceKind":"local","Sources":[{"Component":"main","Name":"aptly-repo"}],"Storage":"filesystem:FPBX17-qa-web","Suite":""}]
Hope it helps!
Pablo