Leftist Potions is a relatively simple mod. When 1.18 came out, Mojang moved the potion icons in the inventory over to the right side of the screen. Anyone familiar with modded Minecraft knows that that's where JEI/REI-type mods put their list of items, meaning potions cut into them and get in the way.
So Leftist Potions simply moves the potion icons back to the left side of the screen, as they should be. Simple as that, and hopefully it works with other mods. Otherwise... oh no.
