Answering a question from Twitter
https://twitter.com/Vindurrin/status/621813610210291714: the emails I got in the past say at the bottom, "You are one of over 9,000 people receiving this email because you have registered with https://translatewiki.net, the wiki localisation platform for translation communities, language communities, and free and open source projects. This newsletter will be sent at most once every month. You can opt-out by visiting translatewiki.net while you are logged in, and checking the box "Do not send me email newsletters" at the bottom of the tab "User profile" in your preferences - although we hope you will not. If you have multiple accounts with the same email address, you have to opt-out for all of them."