kepanoGreat news for plain text interoperability: GitHub has added support for callouts to the GitHub-flavored #markdown using the same syntax @obsidian introduced in Obsidian v0.14 (March 2022)
@obsidian Relevant links:
GitHub discussion
https://github.com/orgs/community/discussions/16925
Obsidian release
https://obsidian.md/changelog/2022-03-14-desktop-v0.14.0/