Your time draws near.

Just wanted to say scheduled signal message. Had this some weeks ago and it drove me crazy. Glad you found out by yourself!

i noticed i get this with scheduled jobs in tasker too. seems like they all use android's alarm system for these sorta things

Alarm is set

I know you say you don't but you must have for the icon to appear

Check your alarms and the days of the week they are set to

Ah you figured it out,

Was going to say if you've not got any alarms set, an application will be (ab)using the system alarm functionality to do something at a scheduled time

Seems a little odd for signal to use it for scheduled messages, but that's what's going on regardless

If you run a tidy ship, you could go through the apps you might suspect, there is a "set an alarm" permission under settings -> apps -> app -> permissions -> three dots -> all permissions.

I don't think stopping / clearing app data makes it go away if it's do persistent, so you might have to resort uninstalling the apps that have this permission until it goes away.

Is your stopwatch running?

Do you have a scheduled do not disturb mode set?

In the notification section of my settings i can see whitch apps sent me notification in chronological order, can you do that?

I noticed this too on my Pixel but only when I open the "drag-down" menu. When I close it the clock's gone..

Do you have an app that does anything at a specific time or a fixed interval eg weekly? Eg. Remind you to go for a run, or prompts you to log an activity like timesheets?

Particularly any new apps or ones that need to access system time and/or date?

Some apps that do some kind of scheduling display the alarm clock icon.

Do you have any app set to do something at a given time? Maybe an automated backup or some kind of automation?

You probably checked, but the stopper or the countdown timer could be running?
Or maybe it's another app that has alarms set with a similar icon. You can check the running apps in settings -> developer settings -> running services

Had the same thing yesterday afternoon. At some point is was gone and it's not back today.

Do you let your network set the time or did you do it manually? Could be a hint that you're off by a minute or so (considering you've checked all the other reasonable things already).

Any other apps installed that may want to set alarms? Maybe a sideload? Calendar app you've tried and not uninstalled?