From "OK" to "". See https://github.com/whatwg/fetch/pull/836 and https://github.com/web-platform-tests/wpt/pull/14144 for tests. The rationale is that few folks will set this field and therefore it'll likely be wrong whenever a non-200 status is used. And "reason phrase" as HTTP calls it is a more or less obsolete field anyway.
Created attachment 380285 [details] Patch
Comment on attachment 380285 [details] Patch Clearing flags on attachment: 380285 Committed r250787: <https://trac.webkit.org/changeset/250787>
All reviewed patches have been landed. Closing bug.
<rdar://problem/56048920>