According to its architecture description ¹, there are no containers or virtualization involved in Deno.
I found deno::CoreIsolate in the source ². Userland process isolation seem to be provided by V8 Isolate.
The execution and security model remind me of recent trend in FaaS, in particular running WebWorkers (or similar), WASM, etc. Found a fascinating presentation about how V8 is used at CloudFlare ³.
"..using V8 isolates instead of containers or VMs, achieving 10x-100x faster cold starts and lower memory footprints.."