Deno is a runtime by creator of Node, Ryan Dahl. It aims at fixing some of the problems in Node. Originally written in Go, Deno is now rewritten in Rust and is in version 0.1.
Scripts should run without any write access by default. Using untrusted utilities like linters will be optional. There is no package.json in Deno, no npm and it is not explicitly compatible with Node.
An important thing to note is that the requirement is Python 2, not Python 3. This is because Chrome V8 scripts still use Python 2.
There were plans to rewrite Deno in Rust when it was originally released in June this year. Dahl mentioned in a GitHub comment: “The reason for not using Go is that it has a rather complex runtime – including a GC. Although I haven’t experienced any problems with that yet, it’s not hard to imagine that down the road that might clash badly with V8’s very complex runtime.”