Emulator

Meatball132: The New Super Mario Bros. Wii mod NewerSMBW (https://newerteam.com/wii/) has a feature called the "replay recorder" that can be activated with the Konami Code [up up down down left right left right 1 2]; this saves title screen/super guide input files to the SD card/USB drive (https://github.com/Newer-Team/NewerSMBW/blob/cw/Kamek/src/replay.S#L98)
Meatball132: this relies on the fact riivolution opens up SD card/USB drive access to games: https://github.com/AerialX/rawksd/blob/master/filemodule/source/file_fat.cpp
Meatball132: dolphin does not reimplement this, though, so it fails to write the file
Meatball132: pretty sure some mario kart mods are using this feature too
Meatball132: i don't know if this is something anyone's even aware of or if there's some viability/security reason this is left out, but thought i'd mention it ¯\_(ツ)_/¯