The authors may see value in engaging with my previous work on the very topic of endoderm development in gastruloids and which in fact even included a dedicated focus on pharyngeal endoderm development. Beyond any possible further support to what presented here (for the authors to evaluate), it certainly would allow to i) correct some present statements about the current state of gastruloid endoderm research that are unfortunately incorrect given the existence of my work, and ii) correctly contextualise some of the findings, possibly allowing to redirect the focus towards the truly novel aspects of the current work.

Given that my work is possibly the only pre-existing piece of work in the gastruloid field that details exactly of "structures that reproducibly establish an anterior-posterior axis and position a Foxa2⁺/Sox17⁺/Cdh1⁺ foregut-like epithelium proximal to Pax1⁺/Pax9⁺ pharyngeal-like endoderm", and given the so clear overlap in the area of investigation, approach, markers considered, and structures obtained (despite the opposite starting point) I am somehow taken aback by the choice to not even mention the existence of such work/data. Regardless of any correction within the text itself, the authors may want to at least cite the two references below if only for correctness to the scientific record.

• "In vitro endoderm emergence and self-organisation in the absence of extraembryonic tissues and embryonic architecture" Stefano Vianello, Matthias P. Lutolf bioRxiv 2020.06.07.138883; doi: https://doi.org/10.1101/2020.06.07.138883"

• Vianello, S. D. (2022). In vitro endoderm emergence and self-organisation in the absence of extraembryonic tissues and embryonic architecture (Publication No. 9201) [PhD thesis, EPFL; Supervised by M. Lütolf]. https://doi.org/10.5075/epfl-thesis-9201 (this one in fact even further detailing the Pax9/Pax1 positive domain compared with the associated preprint)

Sincerely, Stefano D. Vianello