Muluna on data-updates.lua:709 is crashing the game. Here's the code block of this change:

if data.raw.planet["maraxsis"] then
    for _,quality in pairs(data.raw["quality"]) do
        if quality.hidden then goto continue end
        local regulator = data.raw["assembling-machine"]["maraxsis-regulator-fluidbox-" .. quality.name]
        regulator.energy_source.fluid_box.volume = regulator.energy_source.fluid_box.volume*10  <--- this is 709
        ::continue::
    end
end

How can I fix this?

This is something that has to be fixed from Muluna's end; they have a check for the planet Maraxsis, so this code runs during data-updates, but relied on code from Maraxsis that also ran during data-updates; without the optional dependency, Muluna ends up going first and is unable to reference that code.

I ended up integrating this code into Maraxsis directly, so Muluna no longer requires an optional dependency, but they still need to remove this block of compatibility code, as it is no longer necessary. I forgot to mention this to them before uploading; I was using an edited Muluna during my testing that removed this code

Sorry, should've been more specific :P is there a string change that I can do here to continue playing while Muluna isn't updated? I might raise a PR for Muluna too

If you want to fix it locally, you can either remove the entire block of code, or just change the first line from:

if data.raw.planet["maraxsis"] then

to

if mods["maraxsis"] then

That should prevent this block from running when Maraxsis Classic is enabled

I might raise a PR for Muluna too

I've notified the Muluna dev, not sure if or when they'll be able to get around to fixing it

The actual problem is likely a load order issue. Another issue is that this entire code block is obsolete and should have been removed when I stopped interfering with fluid values in other mods.