Mass-radius relation for GN-z11 including young star clusters in the nearby starbursts (NGC253, Leroy et al. 2018; M82, McCrady et al. 2003; McCrady & Graham 2007), low-z blue compact (ESO338-IG04, Östlin et al. 2007) and low-metallicity (SBS0335-052E, Adamo et al. 2010) galaxies. We also plot the values for high-z clusters (Sunburst, Vanzella et al. 2022; Sunrise, Vanzella et al. 2023b; SPT0615-JD1, Adamo et al. 2024), clumps (SMACS0723, Claeyssens et al. 2023), extremely UV-bright SFG (J1316+2614, Marques-Chaves et al. 2024b), and luminous galaxies at redshifts above 8 (GN-z8-LAE, Navarro-Carrera et al. 2024; CEERS-1019, Marques-Chaves et al. 2024a; MACS1149-JD1, Bradač et al. 2024; GN-z9p4, (Curti et al. 2024a; Schaerer et al. 2024); RXJ2129-z95, Williams et al. 2023; MACS0647-JD, Hsiao et al. 2023; GHz2, Calabro et al. 2024; GS-z14-0, Helton et al. 2024). The mass−size relation derived for z = 4–10 galaxies identified with the JWST (Langeroodi & Hjorth 2023) is shown (blue line) as reference. The dotted lines represent the constant stellar mass surface density in units of M_⊙ pc⁻². The line of log₁₀Σ = 5.5 (in red) indicates the observed maximum value in clusters and the nucleus of galaxies, which was also predicted in dense systems under ineffective feedback-regulated conditions (Grudić et al. 2019). The stellar mass of GN-z11 is the average of the values presented in Bunker et al. (2023) and Tacchella et al. (2023).