Thanks for getting in touch! We do not send any of those signals when we attempt to cancel a task. We kill the process that is running it.
If you find that when you do cancel the deployment it is still running then this might be an issue with Bash scripts, but it should attempt to clean up the process.
If that does seem to be the case, could you let me know the distro you are using, and what version of Mono. Hopefully we can replicate it.
It would probably be unlikely that we would send a signal like you mentioned, but the script should be stopped.