You can find the start date and time of your record or activity in the "info.json" file or the "statistics.csv" file.
For an activity: For a record:
In the "statistics.csv" file, the start date and time is indicated in the 2nd column:
In the "info.json" file, the start date and time is indicated under "start_date":
The start date and time is also indicated under Unix epoch time format. The start time corresponds to the number of seconds since January 1st 1970.
In this example, the start time is 382719153664.
However, if you are using the Hxconvertsourcefile software to download your data in the binary format, you can check the box "Save in Posix epoch time (seconds since 1 January 1970)" to have your time converted to epoch directly (therefore no need to divide by 256). This way, the data now in the time column of your "outputrawdata" file can simply be plugged in the epoch & unix converter to give you the actual date.