GPL license violation by Belet Video

[ValdikSS]

There’s Android software called Belet Video.
Official website: https://belet.com.tm/

Belet Video is basically a YouTube and Tiktok proxy, as YouTube and Tiktok are censored in Turkmenistan. The software is created by JAN Tehnologiýa — close-to-government company, in cooperation with Türkmentelekom:

https://business.com.tm/post/6877/new-video-streaming-service-launched-in-turkmenistan

Türkmentelekom state telecommunications company and JAN Tehnologiýa Economic Society launched the Belet Film service, a video streaming platform containing a collection of films, TV series and cartoons.
This new video streaming service is connected to the Internet line, the Turkmen company noted in the statement. This means that the service will be available to all family members. The network speed when using the service reaches up to 8 megabits per second, which allows simultaneous streaming of video to multiple devices.
The customers can subscribe to the Belet Film service through their personal online account or through Turkmentelecom offices. The monthly subscription to the new service costs 30 manats.

It used to use a modified NewPipe as a YouTube core, but now it includes youtube-jextractor, which is licensed under GPLv2. The software developer acknowledged the fact that the program no longer uses NewPipe but fail to provide the source code, both for NewPipe fork and for current youtube-jextractor version.

Could you, please, as an author, contact Belet for source core request?