This is the English version of MarginNote Add-on Development Guide： Introduction | MarginNote Addon Developing Guide (Preview Edition)
Hmmm…… Maybe it’s hard for novice programmers.
I’m from Chinese forum, and here is one inspiring plugin which may provide us a new way to export notes to Obsidian or other Markdown softwares. (Should still be a semi-finished product 
)GitHub - aidenlx/obsidian-bridge: An MarginNote Addon to bridge MarginNote 3 and Obsidian.md.
And here is the demo video by the Add-on Developer: https://bbs.marginnote.cn/t/topic/17140/7