[Zsh]: Questions about manual plugin configuration (without plugin manager)

[z1-0]

home-manager/modules/programs/zsh/plugins/default.nix

Lines 112 to 117 in 0d782ee

	# Add plugin directories to PATH and fpath
	${lib.hm.zsh.define "plugin_dirs" pluginNames}
	for plugin_dir in "''${plugin_dirs[@]}"; do
	path+="${pluginsDir}/$plugin_dir"
	fpath+="${pluginsDir}/$plugin_dir"
	done

Why is it necessary to add plugin_dir/* to both path and fpath here?

@khaneliman