
Twitter has rules that should be followed by all users. But there are times that in practice, those rules aren't that transparent.
When users violate its rules, for example, Twitter can ask the violator to delete the tweets before they can tweet again. But most of the time, those people don't know the reasons of the violation, and how they can appeal to their mistake.
This is where Twitter wants to become more transparent, by providing users the context around deleted tweets. This includes who deleted the tweets and why.
It's a small change, but should make the social platform a better place for its users.

Previously, deleted tweets due to violations would be gone. No explanation whatsoever. This may confuse users because they don't know which Twitter rules they violated.
With the update, Twitter users can clearly see at a deleted tweet, and see a message saying the tweet is no longer available because it violated Twitter‘s rules. The message will have a link to Twitter article that provides more details on how Twitter enforces its rules.
This notice will be displayed on both the account’s profile and the specific tweet for 14 days after the tweet is deleted.
All deleted tweets display the same message, regardless of whether they were removed by the user or the moderators. Those deleted tweets won't have a usable link (all 404-ed), and will no longer appear in others' timeline. Searches for the tweet won't return any result, other than the message from Twitter saying how the tweet is no longer available because it violated its Terms of Service.
"We hope these changes bring more clarity on how and when we our enforce our rules," said Twitter.

The update itself is small, but sure can bolster Twitter's attempt in becoming more transparent when it comes to moderation. After all, Twitter has not only came under fire for its ineffective handling of election manipulation, but also due to its apparent biased handling of political tweets.
Other major change when it comes to the update is that, users who reported it won't have to see the deleted tweets, unless they want to. When they come across a tweet previously reported, the tweet will be greyed out with a 'View' button.
The changes are gradually rolling out to all users.