Preferences for Main?

[MilesCranmer]

I wanted to set preferences for Main so that I can control behavior in my REPL. But seems like it requires a UUID to store it in the cache:

        uuid = Base.PkgId(m).uuid
        if uuid === nothing
            throw(ArgumentError("Module $(m) does not correspond to a loaded package!"))
        end

(from src/utils.jl)

All I really want is to write

[Main]
my_preference = true

Is this possible?