Clarify/provide example/formalize on the fact that BIDS is suitable for "study level" dataset

[yarikoptic]

ATM it is possible and legitimate (AFAIK, didn't check, bids-validator might have its own idea here on not having any sub-*/ , ref @effigies) to have a BIDS dataset

sourcedata/
   bids/
   dicoms/
derivatives/
  fmriprep-1/
dataset_description.json
README
CHANGES

which would contain (raw) bids dataset and derivatives . They might even use datalad and YODA principles (so sourcedata/bids would also be a git submodule within derivatives/fmriprep-1 as it is e.g. in openneuro derivatives).

The question is either we want to define some dedicated DatasetType, e.g. "study", to make it explicit and then also possibly even "forbid" presence of individual sub- folders etc.

Somewhat also relates to BEP035 which defines compositions of datasets (asked the question in BEP035).

attn @jbpoline and @michellewang whom I have been grooming to adopt this mental paradigm in https://github.com/neurodatascience/nipoppy

[effigies]

I think the validator would complain about this, yes.

[yarikoptic]

• it is not an ERROR, just a WARNING, right?
• it is allowed by standard (schema), correct?