when is pg_stat_archiver.stats_reset modified?

Hi all,
running on 12.5, but I guess this does not mind, I cannot understand
when the value of pg_stat_archiver.stats_reset field is modified.
I've executed a pg_stat_reset() but it did not affected the specified field.
I suppose that field is not "resettable" by the administrator, as I
tried to, but then what drives changes?

Thanks,
Luca