BuildSummary.buildStartedAt

Description

The time the build was started, in UTC.

Call .ToLocalTime() to convert to the local timezone for display.

using System;
using UnityEditor;
using UnityEditor.Build.Reporting;
using UnityEngine;

public class BuildSummaryTimes
{
    [MenuItem("Example/Log Build Times")]
    static void LogBuildTimes()
    {
        BuildReport report = BuildReport.GetLatestReport();
        if (report == null)
        {
            Debug.Log("No build report available. Perform a build first.");
            return;
        }

        var summary = report.summary;

        Debug.Log($"Build started : {summary.buildStartedAt.ToLocalTime()} (local) / {summary.buildStartedAt:u} (UTC)");
        Debug.Log($"Build ended   : {summary.buildEndedAt.ToLocalTime()} (local) / {summary.buildEndedAt:u} (UTC)");
        Debug.Log($"Build duration: {summary.totalTime.TotalSeconds:F1} seconds");
    }
}