Incorrect trimming of single pixel line of another color

[RblSb]

import sharp from "sharp";
import fs from "fs";

sharp(fs.readFileSync("image.png")).trim({
	threshold: 0,
	background: "#00000000",
	lineArt: false
}).toFile("trimmed.png");

image:

trimmed result:

But it trims correctly with lineArt: true. I want to ask if this is intended behavior, because lineArt description doesn't really explain much. Maybe it should trim only transparent pixels in both cases?

[RblSb]

I guess this is exactly what it was added for (libvips/libvips#2076), but current documentation doesn't help much in my opinion.