Issue Summary

Jira Cloud returns localized responses in Chinese when the request contains Accept-Language: *, instead of falling back to the default language.

Integrations that send Accept-Language: * may receive responses in an unexpected language, leading to inconsistent behavior across environments and making localization difficult to predict.

Steps to Reproduce

1. Create or use an existing Atlassian service account.
2. Generate an API token for the service account.
3. Authenticate to the Jira Cloud REST API using Basic Authentication with the service account email and API token.
4. Include the following request header: *Accept-Language: **
5. Observe the language of the response.

Expected Results

Jira Cloud should apply the default site language as fallback language when Accept-Language: * is provided.

Actual Results

The API returns localized responses in Chinese, despite no explicit preference for Chinese being provided in the request.

Workaround

Set Accept-Language to the desired language (for example, Accept-Language: en) instead of using Accept-Language: *.

Alternatively, omit the Accept-Language header if appropriate, as this returned English in our testing.