Custom/Local mods for just you

[Suu-Raimu]

I'm unsure if this is already a thing but the only way i've found out how to add my own custom mods to the browser is by hijacking the code of some kind of store mod that will create a folder so i can paste the code into the chrome.css so i can make a mod that i actually want. if this is already a thing to create local mods already that you don't plan to upload to the mod browser shop thing, then i haven't been able to find any documentation on it.