The fall damage multiplier attribute has coloring opposite of what is expected when applied on an item.

How to reproduce:

Give yourself an item with the attribute applied on it:

/give @s brick[minecraft:attribute_modifiers={modifiers:[{type:"minecraft:generic.fall_damage_multiplier",name:"a",operation:"add_value",amount:-0.5,uuid:[I;1,1,1,1],slot:"mainhand"}]}] 

Notice that the attribute description is red despite it having the positive effect of reducing fall damage.