Second anecdata point: Interviewed multiple times for 5-6h in one day, for a medium level Software Engineering role. Either in 4-5 hour-long, mostly technical

Second anecdata point: Interviewed multiple times for 5-6h in one day, for a medium level Software Engineering role. Either in 4-5 hour-long, mostly technical sessions + lunch, or just in "meeting all your potential colleagues, the CEO, COO, etc." for 45min-1h each.