Frequent leaks of Nintendo-related stuff have been happening ever since July with source code for a good deal popular titles, such as F-Zero & Super Mario World, being shared on the internet together with various prototype documents and content. As per a comment by Reddit user ‘GlaDOS_Aperture’, who has been keenly following and describing these leaks, their origin is likely a hack into Nintendo’s internal network done in March 2018 by Wack0 (Zammis Clark) who was arrested in March 2019 due to his hacking activities.
Yesterday, even more Nintendo-related stuff was leaked online albeit this time around, the contents of the leak contain source code for a pretty modern Pokemon title together with more Wii-related stuff showing off TV Remote support and more!