This is not a false alarm: Twitter has officially announced it will start testing an "edit button" this month, an update that they describe as their "most requested feature to date." Tweets will be able to be edited a few times in the 30 minutes after they're posted, as per the company's announcement.
Once a tweet has been edited, it will be given an icon and a timestamp to notify others that the original content has been modified. It will also feature a label that will allow people to see the Tweet’s Edit History, which includes past versions of the Tweet.
The "Edit Tweet" feature is currently being tested out by their internal team and will be rolled out to paying subscribers of Twitter Blue later this month. Eventually, the test will be expanded to a single country so Twitter can examine how people use the edit button on a large scale.