snapd uses its own built-in reporting system similar to apport and uploads crash reports automatically to errors.ubuntu.com. For example this problem.
There is no way for a user to chose the behaviour of snapd and explicitly agree to send error reports automatically or disable it. On Ubuntu Desktop there is a setting in gnome-control-center in “Privacy / Problem Reporting” to do so, snapd should honor this setting.
Thanks @jbl for reporting this issue. There is a PR to fix this https://github.com/snapcore/snapd/pull/4839 now.
In addition to this we should also support a way to disable the problem reports via the core configuration. I pushed https://github.com/snapcore/snapd/pull/4840 for this.