Meta unveiled an app to rival Twitter on Wednesday. It appears to target users looking for an alternative to the social media platform owned — and frequently changed — by Elon Musk. Called Threads, the new offering is billed as a text-based version of Meta’s photo-sharing app Instagram. It is being rolled out in Apple and Google Android app stores in more than 100 countries including the U.S., Britain, Australia, Canada and Japan. Screenshots show a Twitter-like microblogging experience. It suggests that Meta has been gearing up to directly challenge the platform after Musk’s tumultuous ownership has resulted in a series of unpopular changes that have turned off users and advertisers. But Threads has raised data privacy concerns and won’t launch in the European Union.