The fileformat would be a very needed feature to make it possible/easier to make tooling for bi-directional modelling sessions.
I stopped using XMIND because of this.
And of course as @yampeku a free read-only viewer (if that not there) would be a must-have for an open community like ours. A few developers and many views.
That would definitely take away most of my objections to using Xmind.
If they’re in a mood for fun you could also ask them:
“Exactly how long do you think it would take our community to Claude Code a mindmapping tool that’s perfectly aligned with openEHR’s data model, has an open file format, and MCP support?”