It would work by creating a permanent addition to an original tweet, where users could provide context or further explanation for their original message. Then, users would only be able to retweet the clarification, so no one will see the original without it.
The clarification feature could be very useful for people who come under fire if problematic old tweets resurface. It could also be used as an editing tool for minor corrections, sort of like an editing function. However, Dorsey did not confirm if Twitter would fully develop this feature, instead only saying that it is something the platform is exploring.