Sometimes, after clicking "Download mapping" I can see the error:
pyodide.asm.js:10 Uncaught PythonError: Traceback (most recent call last):
File "<exec>", line 118, in download_mapping
FileNotFoundError: [Errno 44] No such file or directory: 'output/22-mapping.tsv'
at new_error (pyodide.asm.js:10:218123)
at pyodide.asm.wasm:0xdef7c
at pyodide.asm.wasm:0xdf077
at Module.callPyObjectKwargs (pyodide.asm.js:10:119233)
at Module.callPyObject (pyodide.asm.js:10:119442)
at PyProxyClass.apply (pyodide.asm.js:10:126886)
at Object.apply (pyodide.asm.js:10:125914)
Sometimes, after clicking "Download mapping" I can see the error: