en.wikipedia.org/wiki/Jerome_Powell

The sentence is inaccurate in two ways.

1. Powell's 2019 balance-sheet expansion did not operate only through overnight repos. In its October 11, 2019 statement, the Federal Reserve said it would purchase Treasury bills at least into the second quarter of 2020 and conduct term and overnight repurchase agreement operations. So the expansion was not just overnight repo lending; it also included outright Treasury-bill purchases.

2. A repo is not a transaction the seller may optionally reverse. The New York Fed defines a repo as the Desk purchasing securities from a counterparty subject to an agreement to resell the securities at a later date. In other words, the unwind is part of the agreement itself, not merely a seller's option.

Because the article says Powell's expansion "operates through overnight repurchase agreements" and describes repos as something "where the seller has the option to reverse the transaction," it misdescribes both the tools the Fed used and the basic structure of a repo.