Is --target-version the minimum or should all be explicitly listed?

With old Black 18.9b0, I had this in pyproject.toml:

[tool.black]
py36 = true

The new Black 19.3b0 warns:

--py36 is deprecated and will be removed in a future version. Use --target-version py36 instead.

The docs say:

  -t, --target-version [py27|py33|py34|py35|py36|py37|py38]
                                  Python versions that should be supported by
                                  Black's output. [default: per-file auto-
                                  detection]
  --py36                          Allow using Python 3.6-only syntax on all
                                  input files.  This will put trailing commas
                                  in function signatures and calls also after
                                  *args and **kwargs. Deprecated; use
                                  --target-version instead. [default: per-file
                                  auto-detection]

I see Black's own pyproject.toml includes:

[tool.black]
target_version = ['py36', 'py37', 'py38']

If I target just py36, does it treat that as a minimum?

Is that the same as ['py36', 'py37', 'py38']?

It recommended to explicitly list all the targetted versions?

Start by reviewing the target-version and deprecated --py36 documentation, along with Black's pyproject.toml example. Verify how a single target version differs from an explicit list, then update the relevant documentation so the supported behavior and recommendation are unambiguous.