Months after Twitter shut down a popular group of sites dedicated to transparency, CEO Jack Dorsey has apologized.

Politwoops -- a group of sites that preserves the deleted tweets of politicians -- was unexpectedly shut down by Twitter last June. On Wednesday, Dorsey issued an apology to developers, specifically mentioning Politwoops, at the company's Flight developer conference in San Francisco, according to Variety.

"Imagine how nerve-racking -- terrifying, even -- tweeting would be if it was immutable and irrevocable?" Twitter told the Open State Foundation, the organization that oversaw Politwoops, at the time of the shutdown. "No one user is more deserving of that ability than another. Indeed, deleting a tweet is an expression of the user's voice."

In a blog post at the time, OSP director Arjan El Fassed criticized Twitter's decision.

"What elected politicians publicly say is a matter of public record," Fassed wrote . "Even when tweets are deleted, its part of parliamentary history. These tweets were once posted and later deleted. What politicians say in public should be available to anyone. This is not about typos but it is a unique insight on how messages from elected politicians can change without notice."

It's unclear if Dorsey's apology means Twitter will reverse its decision.