Most of the fun of using Neovim is tailoring it to your exact needs with custom
configurations. Your configuration can be made up of environment variables,
init.lua/init.vim, and user directories on the runtimepath.
Perhaps though, you want to load neovim with its "factory defaults". You want
to ignore all your custom config and your shada (shared data) file. I wanted
to do just that recently to verify that neovim has the ft-manpage plugin
enabled by default (as opposed to enabled somewhere in the labryinth of my
config files).
The --clean flag does just this. It loads built-in plugins, but none of the
user defined config.
$ nvim --cleanThis is different than nvim -u NONE which excludes all plugins, including
built-in ones.
See man nvim and :help --clean for more details.