The features are in the testing phase or a part of a limited rollout and include Top Requests in Twitter DMs, Auto-Translation of Tweets, and more.
Twitter is also improving few other features with new updates.
Top Requests in DMs
'Top requests' may be classified as requests from verified accounts or that have a larger following. The 'Show top requests first' seems to be similar to 'Top Requests' on Instagram that organizes message requests by important accounts.
The feature on Twitter will show top message requests higher above at the top of the inbox. The option is mainly useful for accounts that have a higher following, and a higher volume of message requests.
Auto-Translation
Within the 'Languages' setting in 'Content Preferences' users may soon have the option to enable auto-translation of Tweets, with a personalization option to choose languages they don't want to be automatically translated.
Shared Content
DM Conversations may soon have 'Shared Content' folders. There is not much information available on the feature but, it would show Tweets, Media such as Photos, and Links shared in the chat in individual folders within the 'Conversation Info' tab.
Descriptions
Another update being worked on by Twitter is explanatory descriptions in the Profile Menu.