They are saved as separate entities (also tagged separately if you have any automated tagging rules set up which trigger for them), and they can be viewed grouped together in the context of their source article in the "Library" tab.
Hmm, in this case, Notado is more like a note-taking system than a bookmarking system. Highlights are just notes that connected with a link. Reminds me of https://lazy.so/, it has a very similar workflow [^1], and the notes of a same link are naturally aggregated as links are entities connect with notes.
