EcmaScript too, but most browser JS runtimes don't (didn't?) support it. It's also part of .NET CIL but only F# uses it so support for it has historically been flakey outside the CLR's main JIT mode.

Safari's JSC (and much more recently, WebAssembly) are the only ones that actually implement it. In practice I don't think it actually ends up being any better than V8, which I believe has some amount of logic to replace them with iterators or trampolines when it can.

IIRC ES6 introduced PTC (Proper Tail Calls), Chrome had an experimental flag for a while but it introduced more issues than it solved (stack traces became a mess and the stack inspection changes came with realistic security concerns). Microsoft and Firefox refused to implement it. Safari refused to un-implement it, and also refused to adopt an opt-in per function flag.

It's crazy how fast javascript has gotten. Ported a classic game earlier this year using all of the new stuff in ES5/6/onwards, the benchmarks are within a couple of percent of what the perf would be were it a standalone game. Runs with 250x monsters at 30x the original tick rate, or >1000x as many monsters at the original tick rate.