All four packs take a design someone else published and adapt it for these sites. A condition of using it is stating the license and where it came from, so every site footer (SiteFooter) carries one line in the data-design-credit spot. The sentence differs by pack: Primer states “Primer Primitives (MIT) · Octicons (MIT)”, and Carbon and shadcn list their own licenses and fonts.
KRDS is stricter. It is released under the Korean public-sector “KOGL Type 1” license, so the exact credit sentence set by the Ministry of the Interior and Safety must appear. For every page built with KRDS, seo:audit looks for that sentence in the footer and reports an error if it is missing. The About page also has a separate “design and font credits” section.
Government emblems, the “official e-government site” strip and the KRDS logo are not brought in, so the sites are not mistaken for government sites. For the same reason Primer and Carbon do not use the GitHub or IBM logos or names.
When to use
Think of it when trimming the footer, or when switching to KRDS. However short the footer gets, the credit line stays.