Most failures are a stale build reference: the hash in the filename no longer exists because the bundle was rebuilt. Re-run the deploy so the HTML and the asset names match again.
Text assets are served with zstd or gzip depending on the
Accept-Encoding header. Pre-compressed variants are not stored separately.
Byte ranges and conditional requests (If-None-Match, If-Modified-Since)
are supported for every regular file.
Hashed bundles under /b/ are kept for twelve months after the last deploy that
referenced them. Images under /img/ are kept until removed by hand.