v0.14.10, explained here: A first look at Obsidian Shared Vaults (v0.14.10 insiders beta) - YouTube
Posting for others as I was digging through the release notes for a bit and couldn’t find it, turned out it was buried there.
Note to be taken it seems to require active Obsidian Sync subscription from all collaborators.
A takeaway from the video is it’s not really for parallel editing with multiple people at the same time.
… require active Obsidian Sync subscription from all collaborators
bummer 
I think it should be possible (with Sychthing for example) for each member of a team to share a read-only folder of their notes. You could not directly edit another’s work, but you could live-comment by linking a note to it, which would show up as a backlink
What about a plugin that copies the markdown into a collaborative online-editor, like Free Collaborative Markdown Editor - onlinemarkdowneditor.dev
after paste, one can simply copy the web-link and share it
(afterwards the plugin could maybe add the link to the note/front-matter?)
Of course this is not something for privacy-aware people, but it’s free! 
I tried to find other free collaborative markdown-editors, but couldn’t find one yet.
Besides this self-hosted solution: New Plugin: Sync to Etherpad Lite for easy web-based collaboration!
Obsidian uses Codemirror under the hood and CM has a collaboration plugin:CodeMirror Collaborative Example
It does require a server though, so the Obsidian team would probably have to implement it instead of it being done as a community plugin.
I wouldn’t mind if it were a plugin. But I haven’t seen any collaboration plugin yet