Some more info from the link:

> MCP Bundles (.mcpb) are zip archives containing a local MCP server and a manifest.json that describes the server and its capabilities. The format is spiritually similar to Chrome extensions (.crx) or VS Code extensions (.vsix), enabling end users to install local MCP servers with a single click.

Just scroll down a little bit. They link what MCPB is.

> Later, I've discovered that Claude Desktop supports MCPB.