After it was spotted in the app's code last week, and Twitter confirmed the coming feature at a press event, the platform has now begun official testing of its new direct message search tool, providing a means to locate specific message threads within your Twitter inbox.
Soul searching? Hard. DM searching? Easy! Go ahead and try out the new DM search bar. We’re testing it out on iOS and web with your most recent DMs. pic.twitter.com/vwGlBjz4B5— Twitter (@Twitter) August 14, 2019
As you can see here, the functionality, at this stage, is limited to searching by display name, not by message content, which seems fairly limited. But it's something, and it's something that many users have called for - and as you can also see, the search results show individual and group message threads that each user is mentioned in, which will also help.
The addition could be of particular value for brands which provide consumer help handles on the platform, which often primarily operate via DMs. Now, you'll be able to more easily locate relevant users to respond to with relevant updates and clarifications, streamlining the process.
The search bar will be available to selected users on both iOS and the web, and applicable to your most recent messages.