Frontend framework they use (NUXT) uses code splitting [1], which means that:

- first request is fast, because you only need to download chunks required for a single page/controller (and you prefetch others in the background)

- changing some parts of codebase requires to re-download only affected chunks, instead of the whole bundle

[1] https://www.telerik.com/blogs/what-you-should-know-code-spli...