Uptime format

Hello, I have this column in my `forever list`

```
uptime        
5:1:19:5.537 
```

How have I to read this value?
537 milliseconds
5 seconds
19 minutes
1 hours
5 ???

Logfile stats say the file was created on `2021-08-03 13:13:04.421706317 +0000`, more than a year ago.
5 cannot be year...

Any idea?