Function set

src/inject/dynamic-theme/stylesheet-proxy.ts:309–315

(target, property, value)

                return true;
            },
            set(target, property, value) {
                target[property as any] = value;
                if (property === 'length') {
                    onAdoptedSheetsChange(node);
                }
                return true;
            },
        });
        adoptedSheetsSourceProxies.set(source, proxy);
        adoptedSheetsProxySources.set(proxy, source);