@Aklapper, I do think the current approach carries a risk of confusion, since I've experienced that confusion myself. Before I figured out that being part of groups and being part of parent tasks could lead to me being autosubscribed to other tasks, I was often quite confused as to why I ended up being subscribed to certain tasks, since there was nothing in the feed indicating it. Among volunteers who don't use Phabricator all the time like you do, I'd be very surprised if this confusion was unique.

You know Phabricator better than I do, so I'm open to whatever solution to this you think is best. But I do think there is an issue here to be addressed. If this isn't the right solution, would you be able to create a task for whatever approach you think would better address it?

I personally prefer not to change the current behavior as I have not yet come across another similar request, and as the task view is already noisy.
Anyone is free to also bring this into an upstream discussion at https://we.phorge.it/ if you believe that there might be different opinions.

Oh wait, reading the task description again:

or auto-subscribed because of a project I am a part of.

Could you elaborate what you mean by this, and point to an example?

If you are a "member" of a project, Phab will not individually subscribe you to tasks.
Some Herald rule might subscribe you to a task but that action would be listed as an entry in the timeline.
Or maybe you have in mind differentiating between a Task Creation Form which already explicitly sets you as a subscriber by default, versus a task author manually adding you to the Subscriber field? But there is no such Form existing in Wikimedia Phabricator currently which does that with your account, I checked the database.

So in my understanding, when you're subscribed to a task and don't see any entry in the task timeline, it's either that a task author added you, or that a Form has your account by default set as subscriber.

I think it may be that if I'm subscribed to a parent task, I get automatically subscribed to any subtasks. There are certainly plenty of tasks that I start getting notifications for that I've never actively touched, and that also don't have any mentions of me in the task history. For some of these, e.g. T399669, I can infer that I was likely added by the task creator because it's relevant to my work. But for others it's less clear. An interface that helps provide information to figure this out I think would make Phabricator a more intuitive platform to use.

In T405245#11203030, @Aklapper wrote:

The current behavior is consistent with setting other fields, e.g. assignee or points […]

For what it's worth, while the current behaviour for the 'subscribers' field is consistent with some other fields, it's also inconsistent with a few others - e.g., setting a task's status/priority does generate its own timeline entry when done at the point of task creation.

In T405245#11248339, @Sdkb wrote:

I think it may be that if I'm subscribed to a parent task, I get automatically subscribed to any subtasks.

Also for what it's worth, T239378: Disable parent task metadata by default for new sub tasks is a task that would stop that happening by default when a new subtask is created.