Minecraft led to Persson becoming one of "Forbes" "World's Billionaires". "Minecraft"s music and sound effects were produced by German musician Daniel Rosenfeld, better known as C418. The background music in "Minecraft" is instrumental ambient music. On 4 March 2011, Rosenfeld released a soundtrack, titled "Minecraft – Volume Alpha"; it includes most of the tracks featured in "Minecraft", as well as other music not featured in the game. The video game blog Kotaku chose the music in "Minecraft" as one of the best video game soundtracks of 2011. On 9 November 2013, Rosenfeld released the second official soundtrack, titled "Minecraft – Volume
Minecraft mods the Bukkit add-on to work on an official modding API, allowing mod developers easier access to the "Minecraft" game files. In May 2015, Mojang announced on social media that they were "still working" on this API, despite announcing it over three years ago. Concern arose following Microsoft's acquisition of Mojang in late 2014. Members of the modding community feared that "Minecraft"s new American owners would put an end to Mojang's established practice of giving free rein to mod developers. Despite the concerns, Microsoft has not announced any changes to Mojang's policies. In April 2015, Microsoft announced that it was adding