CLN: Index._values docstring + Block.internal/external_values
@jbrockmendel this is the "clean" part of https://github.com/pandas-dev/pandas/pull/31037, so if you merge this, I will update the other PR so that only the required changes are in the PR for 1.0.0.
LGTM Is this all internal or would anything leak into `.values`? This is mainly doc updates + removal of an unused internal keyword + duplicated definition. Should be no public consequence. Great thanks @jorisvandenbossche 