I guess that's a fix

public/stdin

@@ -1,9 +0,0 @@
-This file exists because I don't know how to use rollup properly, I guess.
-
-rollup-plugin-svelte in combination with rollup-plugin-scss (as a separate plugin, not in preprocessor) is emitting its stylesheets to a virtual file
-presumably that file gets read by rollup-plugin-scss (or rollup-plugin-postcss, which is used as processor there) as stdin instead of global.scss, putting it into the sourceMap
-
-(All of that is guesswork, I don't really know what's going on)
-
-If you can help me figure out how to fix it, please help me.
-https://github.com/Toby222/

rollup.config.mjs

@@ -63,7 +63,6 @@ export default {
     // The processor (postcss) adds "bundle.css" to the sourceMap
     // but for some reason only in dev mode?
     scss({
-      sourceMap: true,
       outputStyle: production ? "compressed" : "expanded",
       processor() {
         // If this is a separate plugin, it doesn't seem to run (autoprefixer doesn't run)