They have had .is for some time, citation via Wikipedia article for the site. I’ve tried to add inline citations for you if that helps.

https://x.com/archiveis/status/1189322374598053890 ( https://archive.ph/FFQFw )

Archive.today was founded in 2012. The site originally branded itself as archive.today, but changed the primary mirror to archive.is in May 2015.[5] { https://web.archive.org/web/20150601001607/https://blog.arch... } It began to deprecate the archive.is domain in favor of other mirrors in January 2019.[6] { https://web.archive.org/web/20190106000101/https://twitter.c... }