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.
English Wikipedia says the line "will open between Hongmiao and Pinggu in late 2026", and the August 2026 report it cites says the line 年底基本具备开通条件 ("will basically meet the conditions for opening by the end of the year"), so the day stands for late 2026.
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.