The 3011 is one of the weirdest projects around. It is basically an AR receiver with a 1911 frame where the upper should be. It uses custom rails and was released in Nov 2021 by (presumably) The Gatalog member IvanTheTroll.
https://ctrlpew.com/the-3011-3d-printable-1911-frame/
https://odysee.com/@TheGatalog-PrintableFramesReceivers:9/3011-Build-Package:e