applies a layer mask to vector layers without turning them into rasters
Usually, when you apply a mask to a vector layer, this happens:
it loses its vector properties and become a rasterized layer
This is a tool for applying a layer mask to a vector layer while keeping its vector properties, so you can modify your lineart as much as you want without losing quality, and then merging it down to a single layer when you need to!
but warning!the erasing will behave like Vector erasing, and not like raster erasing,
so don't erase parallel to the lineart if you want to make it thinner, just use the Correct Line tools!