Idea is the same as for original "Musical Practice and Performance":
For musicians, students, and enthusiasts. Topics include practice & performance, composition, technique, theory, and history.
There are a lot of people from many countries that knows Russian language. Close to 300 000 000 of people around the world knows Russian language (I hope wikipedia is not lying).
And, I believe, there is lot of native speakers are interested in russian SE for musicians.
Maybe, there are someone interested here also?