As per email:
Cloudflare is deprecating the __cfduid cookie and the cf-request-id headers. The __cfduid cookie will be removed on 10 May 2021 and the cf-request-id headers will be removed on 1 July. We expect that most customers will not have to take action as a result of this removal. [...] Starting on 10 May 2021, we will stop adding a “Set-Cookie” header on all HTTP responses. The last __cfduid cookies will expire 30 days after that.
(cherry picked from commit 747879b4ec6ecdb2777cf6b9d877b51e09922a8c)
368f565942