In Bugzilla, the default preferences are such that the user gets emailed about all bugs he or she reported even if not CC'd. However, I am apparently not subscribed to all my tasks.
To https://bugzillapreview.wmflabs.org/T3064 (migrated from https://bugzilla.wikimedia.org/show_bug.cgi?id=65772), I am "Automatically Subscribed" though not listed as a subscriber. (Does this mean that when someone else subscribes, I am no longer subscribed? Is there even a user guide for Maniphest?)
To https://bugzillapreview.wmflabs.org/T5391 (migrated from https://bugzilla.wikimedia.org/show_bug.cgi?id=67403), I am apparently not subscribed at all. I see "Subscribers None", and the button says "Subscribe", not "Unsubscribe".
In contrast, when I create a new task I am explicitly listed as a subscriber.