Here's a brief overview:
: Added support for the wireless Nintendo Switch Online N64 Controller . Super Mario 3D All-Stars - Nintendo Switch - Amazon.com Super Mario 3D All-Stars Switch NSP ACTUALIZA...
: Games support Joy-Con and Pro Controller functionality with HD Rumble. Super Mario Galaxy Here's a brief overview: : Added support for
Super Mario 3D All-Stars : Complete Guide to the Latest Updates and "Switch 2" Enhancements Super Mario 3D All-Stars Switch NSP ACTUALIZA...
Unlike a standard "remaster" where the source code is rewritten for the new hardware, Nintendo took an emulation-heavy approach. When you dissect the file structure, you find that Nintendo effectively wrapped the original ROMs (or near-original binaries) inside custom-built emulators tailored for the Switch (often utilizing aspects of the open-source projects Nintendo is known for leveraging).
Nintendo released (November 2020) which: