“...900 million years after the Big Bang...”
Not 901 million years or 899 million years. No it’s exactly 900 million years.
And we have 8 more years before the planet is destroyed by the combustion engine and Piltdown Man.
The actual measured redshift of the Balmer line from the Nature paper was 6.2 ± 0.1. This means that at the time the light left the star all the objects in the universe were about 6.2 times closer together with a 10% error. The time estimate should be 900 million years with a 10% error (890 - 990 million years) after the Big Bang. Good catch.
In the meantime we are being treated to the gentle ministrations of Verbal Beatdown Karen.