What does a "" wake reason mean from powerd? This morning, like every morning, I sat down at my laptop but this time the tabs that I normally leave open were closed and Photoshop was trying to quit. 

This was totally unexpected so I tried to work out why this was happening. I went digging into the logs and then via the terminal I looked at the wake logs (see the last few below). 

2019-05-24 03:38:54.643015+0100 0x6a068    Default     0x0                  0      0    kernel: (AppleTopCaseHIDEventDriver) [HID] [ATC] AppleDeviceManagementHIDEventService::processWakeReason Wake reason: Host (0x01)
2019-05-24 03:39:47.402319+0100 0x74       Default     0x0                  0      0    kernel: (AppleACPIPlatform) AppleACPIPlatformPower Wake reason: EC.DarkPME (Maintenance)
2019-05-24 03:39:47.402321+0100 0x74       Default     0x0                  0      0    kernel: (AppleACPIPlatform) AppleACPIPlatformPower Wake reason: EC.DarkPME (Maintenance)
2019-05-24 04:42:14.169247+0100 0x28d      Default     0x0                  63     0    powerd: [powerd:sleepWake] Wake reason: "&lt;private&gt;"  identity: "&lt;private&gt;"
2019-05-24 04:42:15.634941+0100 0x6a5a3    Default     0x0                  0      0    kernel: (AppleTopCaseHIDEventDriver) [HID] [ATC] AppleDeviceManagementHIDEventService::processWakeReason Wake reason: Host (0x01)
2019-05-24 04:43:08.958830+0100 0x74       Default     0x0                  0      0    kernel: (AppleACPIPlatform) AppleACPIPlatformPower Wake reason: RTC (Alarm)
2019-05-24 04:43:08.958832+0100 0x74       Default     0x0                  0      0    kernel: (AppleACPIPlatform) AppleACPIPlatformPower Wake reason: RTC (Alarm)
2019-05-24 06:43:07.636797+0100 0x6abb3    Default     0x0                  0      0    kernel: (AppleTopCaseHIDEventDriver) [HID] [ATC] AppleDeviceManagementHIDEventService::processWakeReason Wake reason: Host (0x01)
2019-05-24 06:44:00.846753+0100 0x74       Default     0x0                  0      0    kernel: (AppleACPIPlatform) AppleACPIPlatformPower Wake reason: RTC (Alarm)
2019-05-24 06:44:00.846755+0100 0x74       Default     0x0                  0      0    kernel: (AppleACPIPlatform) AppleACPIPlatformPower Wake reason: RTC (Alarm)
2019-05-24 08:15:01.640125+0100 0x6b1ce    Default     0x0                  0      0    kernel: (AppleTopCaseHIDEventDriver) [HID] [ATC] AppleDeviceManagementHIDEventService::processWakeReason Wake reason: Host (0x01)


.

There is one that seems different to the others (the one that says Wake reason: "&lt;private&gt;").

I was hoping someone may be able to shed some light onto what this is and satisfy a curious mind?
Starting with macOS Sierra, Apple started a total rebuild of the Console app and the log system.

And, as time progressed, Apple's increased focused on privacy has resulted in some macOS log entries to be redacted  to hide information Apple deems as being sensitive. 

So, for whatever reason, the appearance of &lt;private&gt; denotes information that has been redacted from the logs. Unfortunately, this sometimes renders parts of the logs worthless in terms of troubleshooting a problem.

Regardless, there are many reasons a Mac can wake up from sleep and it's unlikely that it waking up was related to the problem you had this morning.