It might have been better to transliterate "матрёшка" as "matryoshka" rather than "matroschka". Since ё is a "yo" sound, it seems more phonetically accurate.
That's because the matroška container format is often formated as just "matroska" which happens to be a different word. The "š" is the character used for the "sh" sound in slavic languages that use the latin alphabet such as Croatian. "Matroshka" is an anglicized spelling, while "Matroschka" is a germinized spelling.
[1]: https://matroska.org/