@MsLogica it’s not adding anything Obsidian-flavoured to make it work, it uses standard annotation, but also can offer more / other ways. It can add the highlights to PDF as you make them (using standard annotations, also editable by DT), but also keep them in a separate annotation file (which is my personal preference) and dynamically highlight them. It’s fully cross-compatible by default, and can offer additional ways, but only if you want to. This is from the PDF++ settings:
I’ve built something similar for DT a while back:
See for more information the scripts in this thread Stream annotations from your PDF reading sessions with DEVONthink - #34 by mdbraber
I only try to use things that are cross-compatible, without having to use DT, Obsidian or any other tool - which is why Markdown and PDF are favorites. I see DT and other tools more as viewer which offer an additional layer of convenience.