The file under consideration is any file under `/data/system/usagestats/0/daily/`. The entries it has are like:
<package lastTimeActive="77497976" package="com.android.settings" timeActive="471657" lastEvent="2" />
<package lastTimeActive="50486897" package="com.android.dialer" timeActive="180327" lastEvent="2" />
<package lastTimeActive="83158956" package="com.cyanogenmod.trebuchet" timeActive="461860" lastEvent="2" />
<package lastTimeActive="59444603" package="com.slovoed.oald" timeActive="405608" lastEvent="2" />
[Here](http://pastebin.com/bQexC3w3) is the complete text for the file `1438905600000`.
The value `77497976` doesn't seem to be Unix Time, and `471657` seems to be [milliseconds](http://www.unitconversion.org/time/milliseconds-to-minutes-conversion.html).
I added that value into the value mentioned in file name i.e. `1438905600000` + `77497976`, and the converted resultant of `1438983097976` [here](http://www.epochconverter.com/) doesn't reflect the actual result shown in GUI here:
<sub>(Click image to enlarge; screenshot was taken on Aug 8, 2015 at 05:08 AM)</sub>
[<img src="https://i.sstatic.net/nHScK.png" width="210" height="350" alt="IMG: Screenshot of Usage Statistics" title="">][1]
Package name of apps shown in screenshot whose raw time-stamps you can see in the file:
* Settings → `com.android.settings`
* Dialer → `com.android.dialer`
* Launcher3 → `com.cyanogenmod.trebuchet`
* SQLite Editor → `com.speedsoftware.sqleditor`
* Titanium Backup → `com.keramidas.titaniumbackup`
* OALD → `com.slovoed.oald`
* ES File Explorer → `com.estrongs.android.pop`
* Clock → `com.android.deskclock`
`adb shell su -c 'dumpsys usagestats'` is of no help since it gives no output to me.
[In Android 4.x, it is easy to understand the time-stamp](https://android.stackexchange.com/a/116633/96277) (mainly the "last time used") because Unix Time is written in the logs, and you can convert it into human readable time easily.
I looked at [UsageStats](https://developer.android.com/reference/android/app/usage/UsageStats.html), [UsageStatsManager](https://developer.android.com/reference/android/app/usage/UsageStatsManager.html), [UsageStatsActivity](http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android-apps/5.0.2_r1/com/android/settings/UsageStatsActivity.java#UsageStatsActivity.UsageStatsAdapter) but couldn't understand how the time gets converted.
---
Alternatively, is there a schema which Lollipop follows to write entries in those usage-stats file? Perhaps, that can help to figure out in conversion?
I'm using a rooted OnePlus One running CM12.
[1]: https://i.sstatic.net/nHScK.png