Incorrect Content-Encoding header on .bz2 files breaks proxy downloads

[JacobCoffee]

Summary

.bz2 files served from downloads.python.org incorrectly set Content-Encoding: bzip2 in response headers. bzip2 is not a valid HTTP content-encoding value, causing SSL-inspecting proxies to drop the connection with an empty HTTP response.

Current behavior

HTTP/2 200
content-type: application/x-tar
content-encoding: bzip2

The file is not transfer-encoded — it's a .tar.bz2 archive. Setting Content-Encoding: bzip2 tells intermediaries the payload uses bzip2 at the transport layer, which they don't support and may reject per RFC 9110.

Expected behavior

Serve with Content-Type: application/x-bzip2 (or application/x-tar) and no Content-Encoding header. This matches how Apache serves .bz2 files (e.g., downloads.apache.org).

Impact

Users behind SSL-inspecting proxies (corporate/government networks) cannot download .bz2 files from downloads.python.org. Reported via webmaster@ on 2026-04-09.

Likely fix

Update the nginx configuration on the downloads CDN to stop setting Content-Encoding: bzip2 for .bz2 files.

[linear]

PYORG-2972

[JacobCoffee]

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