What is the "Uncategorized" Android Notification Channel and when does it appear? : <p>While transitioning an application to Android O, I have noticed a strange thing. Sometimes my foreground service notification goes into a channel that I have not made, called "Uncategorized". I have no idea how or when this happens. </p>

<p>The channels are always created before the notifications start being posted, and the ID of the channel is correct. I have tried putting in a random String as the channel ID to see if I could reproduce the issue, but the notification just doesn't get posted in that case. So it seems to be some weird case when the channel was already created before.</p>

<p>This is the channel's page:</p>

<p><a href="https://i.stack.imgur.com/9fRT2.png" rel="noreferrer"><img src="https://i.stack.imgur.com/9fRT2.png" alt="Uncategorized channel page"></a></p>

<p>And this is the channel appearing in the list of all channels of the app (note, I have removed the icon for privacy reasons).</p>

<p><a href="https://i.stack.imgur.com/Lp8iA.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Lp8iA.png" alt="The channel presented in the list of all channels"></a></p>

<p>Does anyone have any experience with this and could they explain when this can happen? Unfortunately, I found no documentation regarding this, and heard nothing about it in the Google I/O talks.</p>
