Microsoft's GitHub platform isn't exactly known for activism. But in China, the code-sharing platform is now home to an online protest movement demanding better working conditions at the country's technology firms.

The GitHub repository at "996.ICU" has been calling out Chinese tech companies that pressure their employees to work from 9 a.m. to 9 p.m., six days per week. Since it went up last month, the page has been starred over 229,000 times, making it one of the most popular GitHub repositories on the site.

But now a group of Microsoft employees are worried the Chinese government will force their employer to take the page down. So in response, they've been circulating an internal letter, urging Microsoft to stand up to any potential pressure to censor the GitHub page.

"We encourage Microsoft and GitHub, companies which firmly believe in a healthy work-life balance, to keep the 996.ICU GitHub repository uncensored and available to everyone," reads the letter, which was shared with PCMag and started circulating internally on Sunday.

GitHub, which Microsoft acquired last year for $7.5 billion, is a popular site for programmers all over the world to share and improve computer code. But last month, a group of anonymous Chinese users decided to use the platform to call attention to the grueling work schedules at their own employers, which Chinese programmers joke can send a person to a hospital's intensive care unit, or ICU.

The GitHub repository now hosts a list of over 140 Chinese companies that allegedly demand their employees work 60 hours a week. Many foreign media outlets have also reported on the protest page.

But reportedly, some attempts have been made to censor mention of the 996.ICU repository within China. Domestic browsers from Tencent, Qihoo 360, and Xiaomi recently prevented users from visiting the GitHub page, according to Abacus.

It's why a group of Microsoft employees based largely in the US decided to circulate a protest letter calling on Redmond to protect the GitHub page from censorship. "While it is still unknown as to whether these companies are blocking the repository on their own accord, we must entertain the possibility that Microsoft and GitHub will be pressured to remove the repository as well," the letter reads.

So far, Microsoft hasn't responded to a request for comment. So it isn't clear if the company has been in contact with the Chinese government about the issue. But Microsoft's two other web properties, Bing and LinkedIn, have been forced to comply with the country's strict censorship demands.

Of course, the Chinese government could take drastic action and block GitHub in its entirety. The country previously cut off access to Facebook, Google, and Twitter for their ability to share uncensored information. To visit such sites from within China, you'll have to use a VPN.

But for now, GitHub remains online in China. The government also appears to be allowing at least some discussion of "996" labor-related issues in local press and on Chinese social media.