Why have I recently started receiving emails from https://open.cdash.org/index.php?project=VTK&date=2021-04-22
You’ll get those if you have recently contributed to VTK. The intent is to alert folks if there are problems that their recent contributions may have caused. After a night (maybe two), you won’t get them anymore.
You can change your settings if you log in to open.cdash.org and go to the VTK project. This is likely the direct link once you have logged in (I don’t know how dynamic the links are on cdash.org).
Login to what? Gitlab? I have never registered on CDash.
On CDash.org. I suspect it is a CDash project-level setting that is enabled that sends emails to recent committers about failing/passing tests. I’m not an admin for the project, so I can’t answer conclusively.