Bugzilla

Firefox doesn't send the `Sec-CH-UA` header as part of HTTPS requests.

This seems to be needed (maybe for no good reason) in order to get functional results on bug 1972496.  In that bug, the website doesn't send the `access-control-allow-origin` header as part of its response *unless* the request includes a value for `sec-ch-ua` (e.g. just adding
```
  -H 'sec-ch-ua: ""' \
```

Hence, filing this bug on considering adding support for this header (perhaps optional or site-specific if we're not sure we want to broadly support it yet).

MDN page: https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Sec-CH-UA
One WPT test at least: https://wpt.fyi/results/client-hints/sec-ch-ua.https.html

Firefox doesn't send the `Sec-CH-UA` header as part of HTTPS requests.

This seems to be needed (maybe for no good reason) in order to get functional results on bug 1972496.  In that bug, the website doesn't send the `access-control-allow-origin` header as part of its response *unless* the request includes a value for `sec-ch-ua` (e.g. just adding
`-H 'sec-ch-ua: ""'` to the curl version of Firefox's fetch request there is sufficient to get e.g. `access-control-allow-origin: https://terminal.us-west-1.run.claw.cloud` in the response headers, which is needed for the site to work.)

Hence, filing this bug on considering adding support for this `Sec-CH-UA` header (perhaps optional or site-specific if we're not sure we want to broadly support it yet).

MDN page: https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Sec-CH-UA
One WPT test at least: https://wpt.fyi/results/client-hints/sec-ch-ua.https.html