A former engineer for Twitter Inc. claims the business let him go days after Elon Musk bought the company because he created a tool that allowed staff to save crucial documents in case of mass layoffs.

The engineer, Emmanuel Cornet, complained to the U.S. National Labor Relations Board on Monday, claiming that sharing the software on an internal Twitter messaging channel constituted protected activity.

“Protected activities” are actions that workers can take without fear of employer retaliation under U.S. labor law.

No comment was made by Twitter on the matter.

Cornet, who was based in San Francisco, claimed in the complaint that he was let go on November 1—just a few days before Musk, the richest man in the world, announced plans to cut costs by firing about half of Twitter’s 7,500 employees.

Cornet and four other Twitter employees filed a lawsuit against the social media company on Friday in federal court in California, alleging that the company had broken laws requiring employers to give 60 days’ notice before mass layoffs.

Musk claimed in a series of tweets on Friday that Twitter provided 90 days of severance pay to employees who were let go, which may have satisfied Twitter’s legal obligations to provide notice.

According to Cornet’s complaint, he created a Google Chrome extension late last month to enable employees to download emails from their Twitter accounts amid rumors of mass layoffs at Twitter. According to him, doing so would guarantee that employees could save crucial documents like statements reflecting their Twitter stock, performance reviews, and other human resource documents.

On the same day that he published the extension and shared a link to it on an internal Twitter messaging channel, according to Cornet, he was fired. Later that day, Twitter reportedly removed the link, as stated in the complaint.

If the NLRB files a complaint against Twitter and ultimately rules in Cornet’s favor, it may order that the company post a notice informing workers of their rights under federal labor law and that Cornet be reinstated with back pay.

(Adapted from BusinessToday.in)