For example, imagine that on Monday you have nothing in your brokerage account except shares of a specific stock, which you sell that morning for $10,000. The trade will settle on Thursday.
It's further down the (infinite-scrolling) page, under the title "Why Wait Three Days to Sell Stock?". Looks like much of the material there is older, but this section at least has been updated to mention the change to T+2.
Directly from the link:
"In 2017, the SEC amended the T+3 settlement cycle to a T+2 settlement cycle, effectively shortening the three-day rule to a two-day rule."