Feature request: Provide low-entropy UACH on updateURL fetches #1240
Description
PA updateURL fetches' utility could be improved with the inclusion of low entropy UACH. Opening this issue per suggestion in the 31 July WICG discussion. While buyers can work around by encoding the info into the updateURL, this adds complexity and unnecessarily consumes IG on-device space.
Chrome Canary net-log trace from 31-July:
GET /fetch/updateurl HTTP/1.1
Connection: keep-alive
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: no-cors
Sec-Fetch-Dest: empty
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36
Accept-Encoding: gzip, deflate, br, zstd
Accept-Language: en-US,en;q=0.9