browser-globals.test.js loads every page module through vm with a fake window, the way the pages do, and asserts the global each one exposes (HtmlEscape/escapeHtml, DataActions, ApiClient, ListState, SseStream, PngMetadata, ViewRouter, PromptListSort, ComfyMetadata). sse-stream gains cases for a POST body, missing handlers and close() before or during delivery. Every pure module is above 85% line coverage under node --test --experimental-test-coverage.