• WHOIS points to a "Denis Petrov" in Prague
• Share menu has buttons for Reddit, VKontakte, Twitter, Pinboard, and Livejournal. Eyebrow raising. VK is Russian, and so is LJ nowadays. Pinboard (notable as successor of del.icio.us) is American, coincidentally founded by a Polish immigrant.
• With a sizable dose of confirmation bias, the mistakes in the English of the site and blog do feel appropriately Slavic
It's stated to be privately funded with costs around US$4000/month, began accepting donations in 2016 (https://wiki.archiveteam.org/index.php/Archive.today#Vital_S...)