Failed to load mods: planet-rabbasca/util.lua:55: attempt to concatenate field 'subgroup' (a nil value)
stack traceback:
planet-rabbasca/util.lua:55: in function 'create_infused_thing_with_effect'
planet-rabbasca/util.lua:110: in function 'create_ears_variant'
planet-rabbasca/scripts/create-ears-variants.lua:9: in main chunk
[C]: in function 'require'
planet-rabbasca/data-updates.lua:18: in main chunk

Thanks for the report. Should be fixed with 0.5.3

Thanks for the fix. sadly a new crash follows.

Failed to load mods: planet-rabbasca/scripts/create-ears-variants.lua:41: attempt to index field '?' (a nil value)
stack traceback:
planet-rabbasca/scripts/create-ears-variants.lua:41: in main chunk
[C]: in function 'require'
planet-rabbasca/data-updates.lua:15: in main chunk

Just ran into that too. Fixed in 0.5.4

you fixed your bug but created one for ReverseFactory

Failed to load mods: The given sprite rectangle (left_top=0x0, right_bottom=64x64) is outside the actual sprite size (left_top=0x0, right_bottom=32x32).
See the log file for more information.: reverse-factory/graphics/item/reverse-factory-1.png

Which i will report there & come back with a reference link.

Link: https://mods.factorio.com/mod/reverse-factory/discussion/6919412d9e361c005b708300

That was an incompatibility on my side. Fixed in 0.5.5.