see no way send

 try {
   const trimmed = responseText ? responseText.trim() : "";
   if (trimmed.startsWith("<") || trimmed.startsWith("
})();

Bugzilla Report Package Product: Developer Tools Component: General / Debugger Title: [Source Map Loader] Worker crash due to unhandled JSON.parse error on non-JSON/HTML responses in fetchSourceMap.js Description: When fetching source maps in a worker context, fetchSourceMap.js occasionally encounters an unexpected non-JSON response (such as an HTML error page or 404 response starting with <!DOCTYPE html>). This causes an unhandled JSON.parse exception at line 83 (_fetch), crashing the source map consumer. Stack Trace: Plaintext Source map error: Error: JSON.parse: unexpected character at line 1 column 1 of the JSON data Stack in the worker: parseSourceMapInput@resource://devtools/client/shared/vendor/source-map/lib/util.js:163:15 _factory@resource://devtools/client/shared/vendor/source-map/lib/source-map-consumer.js:1069:22 SourceMapConsumer@resource://devtools/client/shared/vendor/source-map/lib/source-map-consumer.js:26:12 _fetch@resource://devtools/client/shared/source-map-loader/utils/fetchSourceMap.js:83:19 Proposed Patch (fetchSourceMap.js - Line 83): JavaScript // Replace direct unhandled parse at line 83 with safe parsing: const sourceMap = (() => { try { const trimmed = responseText ? responseText.trim() : ""; if (trimmed.startsWith("<") || trimmed.startsWith("<!DOCTYPE")) { throw new Error("Received HTML instead of JSON"); } return JSON.parse(responseText); } catch (err) { console.warn(`SourceMapLoader: Failed to parse source map.`, err); return null; } })();