and

The falsy values are false, 0, any nil pointer or interface value, any array, slice, map, or string of length zero, and zero time.Time values.

Everything else is truthy.

{{ and 1 0 "" }} → 0 (int)
{{ and 1 false 0 }} → false (bool)

{{ and 1 2 3 }} → 3 (int)
{{ and "a" "b" "c" }} → c (string)
{{ and "a" 1 true }} → true (bool)

See Go’s text/template documentation for more information.