Whether these emulators support operating systems for these consoles is unknown; it must be looked into further. Consoles without meaningful OSes are not included.

Nintendo Entertainment System – Project Nested

https://github.com/Myself086/Project-Nested https://emulation.gametechwiki.com/index.php/Project_Nested

High level Linux-like OS Running on a SNES. The OS is intended to be used with a custom cart with the bios and other requirements. The exact requirements are not known at this time. Minor Modifications to the SNES Hardware may be necessary.

No emulator support.

https://github.com/chorman0773/snes9x (“emulator virtual machine”)

https://github.com/chorman0773/SNES-OS

https://github.com/chorman0773/SNES-OS-rs

what looks to be a compiled version of it (dos.hex) and it does seem to run in an emulator (after being converted to a binary).

Official Nintendo-crafted DOS clone, found in the July ‘20 files leak. Look in “other\SFC\SFC_50SEC~3_YK3YV~S_67V3K~2\tool\” sfxdos folder.

The info for this is quite widely known, and it doesn’t exactly fit the “web browsing”, but it’s close.