I don't, sorry. I just know it's something some implementations opt-in to (especially drop-in replacements to bash). It's behavior I've observed quite a bit and

I don't, sorry. I just know it's something some implementations opt-in to (especially drop-in replacements to bash). It's behavior I've observed quite a bit and have leveraged it in some cases to improve the performance of some critical bash scripts over the years. I'd also be interested in some prose about it.