GLupen64 has been renamed to 'Mupen64plus libretro'. This will be an upstream-compatible libretro fork that uses the GLideN64 graphics plugin. We will also be maintaining this ourselves from now on.
The old 'mupen64plus libretro' core has meanwhile been renamed to 'ParaLLEl N64', and this single core now has both GL and Vulkan renderers integrated! It will also switch on the fly to Vulkan or GL mode depending on which video driver you have selected in RetroArch!
ParaLLel N64 is our 'hard fork' of Mupen64Plus where we have added numerous enhancements and changes so that it becomes pretty much its own entity.
With these changes, we hope to satisfy both people who want a core to stay as close to upstream as possible, and the people who like to see a core that plays more to libretro and RetroArch's strengths and has numerous enhancements added on top!