In https://gerrit.wikimedia.org/r/#/c/179105/, a domain level cookie with a short expiration time is used as a token to indicate that the translator went through the normal translation workflow. Note that this cookie is not host-level, but domain-level, with the domain being '.wikipedia.org' for Wikipedia. This allows Content Translation (CX) to redirect users between source and target language wikis.
A user going through the normal translaiton workflow will see the legal notice about the license of the content; hence, this is important.
The first phase of deployment for CX is scheduled for Jan. 15, so please review this cookie and flag it if you notice any issues.