It’s IPO season in the United States, despite market volatility in recent months and historical blockers like an impending election. Given the public market’s return to form since March lows — paticularly the outperformance of the Nasdaq index and other tech shares — some venture-backed companies are trying to get out while the new offerings are welcome. The Exchange is a daily look at startups and the private markets for Extra Crunch subscribers; use code EXCHANGE to get full access and take 25% off your subscription. Used-car marketplace Vroom is…