Maraxis just updated to 2.1 and I tried adding it but got the following error on loading in:

Failed to load mods: planet-rabbasca/api.lua:214: attempt to concatenate local 'original_replacement' (a table value)
stack traceback:
planet-rabbasca/api.lua:214: in function 'create_ears_entity'
planet-rabbasca/api.lua:231: in function 'create_infused_thing_with_effect'
planet-rabbasca/api.lua:281: in function 'create_ears_variant'
planet-rabbasca/scripts/create-ears-variants.lua:43: in main chunk
[C]: in function 'require'
planet-rabbasca/data-final-fixes.lua:43: in main chunk

Removing Maraxis fixes this issue. I don't actually know anything about writing mods but I've played on saves in 2.0 that had both maraxis and rabbasca installed that loaded without this issue so I'm hoping that this is a fixable issue.

same

Thanks for the report, fixed in 0.19.5.
This means that maraxsis is using a new planetslib feature that rabbasca picks up on. So now placing a hydro plant with EARS in space will inherit the bonus module slots, just like when placing the default non-EARS plant.

my hero!