"Astronomers led by Rohan Naidu of the Harvard–Smithsonian Center for Astrophysics discovered the two candidate galaxies, called GLASS-z11 and GLASS-z13, in the first batch of data from GLASS. The galaxies' designations come from the fact that astronomers have measured their "redshifts" to be 11 and 13 respectively."
Impressive here. The paper I read on this find is Two Remarkably Luminous Galaxy Candidates at z ≈ 11 − 13 Revealed by JWST,
2207.09434.pdf (arxiv.org)
I note 12-pages. "6. SUMMARY & OUTLOOK This paper presented a search for luminous z > 10 galaxies across the two JWST Early Release Science programs in extragalactic fields. We find the following – • We identify two particularly luminous sources in the GLASS ERS program. These sources, GL-z11 and GL-z13, have continuum magnitudes of ∼ 27 at 2 µm and display dramatic > 2 mag breaks in their SEDs that are best fit as Lyman breaks occurring at redshifts of z ≈ 11 and z ≈ 13 respectively. [Fig. 1, Fig. 2, §4.1] • SED modeling of these sources shows they have properties (e.g., β slopes, specific star-formation rates) expected of z > 10 galaxies. These systems are a billion solar mass galaxies, having built up their mass only < 300 − 400 Myrs after the Big Bang. [Table 3, §4.3...If these candidates are confirmed spectroscopically, and indeed two z ≈ 11 − 13 candidates lie awaiting discovery in every ∼50 arcmin2 extragalactic field, it is clear that JWST will prove highly successful in pushing the cosmic frontier all the way to the brink of the Big Bang."
[My note. The comment near the end of the paper indicates that GL-z13 remains to be spectroscopically determined redshift, presently Lyman break method. The phys.org report is out too, Webb telescope may have already found most distant known galaxy,
https://phys.org/news/2022-07-webb-telescope-distant-galaxy.html, 21-July-2022, "Though GLASS-z13 existed in the earliest era of the universe, its exact age remains unknown as it could have formed anytime within the first 300 million years."
My note, using cosmology calculators like
https://lambda.gsfc.nasa.gov/toolbox/calculators.html or
https://www.kempner.net/cosmic.php and z = 13, you will get age at redshift near 300 Myr old after the BB event. The comoving radial distance is more than 33 Gly distance so 4D space expanding faster than c velocity is required to accept the interpretation and age calculation too.