Commenting here to help the next guy:
Plugins are under 'Marketplace' and you are looking for 'Linear Advance Settings'
Then you can set {material_linear_advance_factor} from the right side panel in Cura.
To use it you will have to add a line like 'M900 K{material_linear_advance_factor}' to your start g-code.
I follow that line with 'M900 W{line_width} H{layer_height} D{material_diameter}' like it says in the readme:
https://github.com/fieldofview/LinearAdvanceSettingPlugin
I don't think this works with adaptive layer heights, not perfectly anyway. I think we would have to include 'M900 W{line_width} H{layer_height} D{material_diameter}' at each layer, or each layer that is different from the last. If we wanted to adjust the Linear advance perfectly for different layers in prints sliced with adaptive layers enabled. If someone wants to test this, it could be hacked tother with a search/replace in the g-code post processor.