Live Studio, TikTok’s new livestreaming app for Windows, supposedly uses code from the free livestreaming program Open Broadcaster Software OBS. This would typically not pose an issue when done properly because OBS is open source — however, TikTok purportedly fails to adhere to OBS’ licensing requirements.

The situation unravelled on Twitter after a user posted screenshots of what appears to be Live Studio’s code. The programmer who originally took the screenshots alleges that the app “is an illegal fork of OBS” and also claims that TikTok used OBS and then slapped its own user interface on top.

If TikTok does make use of OBS’ code, the platform is required to make the source code publicly available in accordance with the GNU General Public License (GPL), version 2. If TikTok fails to do so, OBS could potentially take legal action against the platform.

Ben Torell, the business developer for OBS, later replied to that tweet in agreement, but noted that OBS is open to working with TikTok: “We have a commitment to dealing with GPL violations in good faith, and in the case of TikTok/ByteDance we would be happy to have a friendly working relationship with them as long as they comply with the license.” The Trump Media and Technology Group (TMTG) got in trouble for a similar reason in October, as it failed to make the source code for Truth, Donald Trump’s upcoming social network, publicly available after using the open-source Mastodon to build the site.

TikTok quietly started testing Live Studio with a small group of users just a few days ago. In its current state, it appears to be a barebones streaming software with the ability to let users broadcast live, whether from a camera, phone, game, or program.