How does Binance calculate the open and close values in the candle plot for Spot Trading?

Hi. I've heard that the open and close values are associated to the first and last transaction of the time vary (day, week...). Nevertheless, I observed the open worth is identical because the shut value of the previous bin, which sounds weird to me. As cryptos are decentralized, shouldn't we now have totally different values for that? Couldn't we've got an outlier transaction in the first transaction of the day that's totally different from the last transaction of the day past?

Also, costs in the dashboard (Spot trading) are calculated based mostly on solely Binance transactions or different exterior sources (like other platforms)?