f="https://en.wikipedia.org/wiki/Greenwich_Mean_Time">Greenwich Mean
Time</a> (<abbr>GMT</abbr>) with days beginning at midnight;
for timestamps after 1960 this is more precisely <a
href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time">Coordinated
Universal Time</a> (<abbr>UTC</abbr>).
The database also records when daylight saving time was in use,
along with some time zone abbreviations such as <abbr>EST</abbr>
for Eastern Standard Time in the <abbr>US</abbr>.</p>
</section>

<section>
<h2 id="do