The static handler sent no Cache-Control, so browsers fell back to
heuristic caching (10% of age since Last-Modified) and kept serving a
stale reader.js for hours after a deploy — fixed web bugs reported as
"not fixed". no-cache forces revalidation every load; the filesystem
Last-Modified/If-Modified-Since pair keeps unchanged loads cheap.
Found while closing out the PDF adjust v2 session: the user's Chrome
was running a pre-endpoint bundle, which read as "the web has not
been fixed".
John O'Keefe
a3ecac3507