The first entry is always the pin's source. Overall confidence is a weighted average of how firmly each reference supports the start and end times used above; a reference counts half as much for every 180 days older than the newest.
Wikipedia[2] dates the current building's completion to 1909 - "essentially finished by mid-1909" - with the Flinders Street verandah and the concourse roof finished only after the official opening in 1910. No source gives an exact day, so the date sits on the last day of 1909.
Wikipedia and the Victorian government's own "170 years" retrospective both confirm the present building was completed in 1910, corroborating the video's claim independently.
Something missing or wrong? Say it in your own words: a link that backs this pin up, a different start or end date and why, or a fact it lacks or gets wrong. The AI checks it against this pin's sources, searches for better ones, and adds any page that backs you up. The pin's own sources still count most.