Variable: display-time-world-list

Alist of time zones and places for `display-time-world' to display.
Each element has the form (TIMEZONE LABEL).
TIMEZONE should be in a format supported by your system. See the
documentation of `zoneinfo-style-world-list' and
`legacy-style-world-list' for two widely used formats. LABEL is
a string to display as the label of that TIMEZONE's time.