guarantees on digits of floating point values

As a test, I checked 1000021 digits of exp(1),

my(N=10^6+21); localprec(N); exp(1) * 10^(N-1)\1

against https://apod.nasa.gov/htmltest/gifcity/e.1mil
and all digits matched. :)

Is there a guarantee in the documentation about such?
Similar to how all primes up to 2^64 are guaranteed.

-- Greetings, Ruud