Yes — they're generated using the browser's native Web Crypto API (crypto.randomUUID or crypto.getRandomValues), not Math.random(), so they're suitable for real unique identifiers.
Version 4 (random), the most commonly used format for databases, APIs, and general application use today.
Yes — choose a count (1, 5, 10, 20, or 50) and click Generate to get that many at once, one per line.