Banjo-Kazooie and Banjo-Tooie on the Evercade Nexus use the original Rare source code, which included 'a load of stuff' that the studio didn't even know about, Blaze Entertainment says

Blaze Entertainment has discovered hidden features in the source code of Banjo-Kazooie and Banjo-Tooie while working on the ports for the Evercade Nexus handheld console. The Evercade Nexus is set to launch on October 30 and will include the Banjo-Kazooie Double Pack, featuring both games with enhanced performance and graphical improvements.

Sean Cleaver, head of communications at Blaze Entertainment, collaborated closely with Rare, the original creators of the games, who provided them with the original N64 source code. This collaboration led to the team uncovering a wealth of unreleased content, such as unused tracks and a level editor. Cleaver emphasized the excitement of working with Rare, who shared the source code and revealed hidden features that even the creators were unaware of.