It's usually listed in the benefits. Burnout is very inefficient and any place that tries to accomplish anything will be aware of its drawbacks.

These are places that tell you to stop thinking of work after work. They have classes on preventing burnout, meditation classes, lots of vacations. Ironically, a lot of those places don't actually advertise work-life balance, because they enjoy going to work and often end up at the office longet than usual. The best hint is usually generosity - you get the impression they're not trying to lowball you or squeeze as much out of you as possible, and they often have gifts when you even interview.

Small companies are often really bad at burnout mitigation - you end up with situations where everyone is always too busy, and there's no docs, no specs, no tests, no source control, no leadership. You're often taking on two jobs with little responsibility, little pay, but also nobody to replace you when you need time off. It can be light but emotionally exhausting, especially when you know the project you worked on will run out of funds.

I've tried long breaks of months and they never really worked for me, often pushing me deeper into burnout. What always works is actually working a little more. First time it was teaching for certifications, which was something with no chance of failure but still tiring. Second was dumping a lot of effort into a side project. Again no chance of failure, but tiring.

So I'd say the cure to burnout is actually tiring yourself out on something you enjoy, something meaningful but can't fail at.