title: Merge changes on Draw.io (diagrams.net) files with Git
body: <p><strong>Context</strong>: at my company, we document our architecture with multi-page Draw.io diagrams. These diagrams are included in a statically-generated documentation website. This works well, especially because we can link diagrams and website content.</p>
  <p><strong>Problem</strong>: now that the documentation has grown, we sometimes have several developer modifying the same Draw.io diagram in different Pull Requests. And Draw.io XML format is not very good at merging... so we had to resolve to &quot;soft locking&quot; the diagrams (with good old communication and .OWNERS files) to avoid 2 PR to modify the diagram at the same time.</p>
  <p>I did not find any reference to a merging plugin. Latest versions of Draw.io desktop app and web editor allow collaborative editing, but I didn't find a way to start from that to write a merge tool. Any ideas how to proceed ? Do you have recommendations on the best way to handle that issue ?</p>