Get ADB access to your Xplora Watch. Pull apps, analyze security, or build your own thing on a mediocre Android smartwatch.
Open the Settings app on the watch, navigate to about the watch. Find the SW Version entry and tap on it ten times. A PIN code entry form should open up.
Enter your watch's IMEI above and select the right PIN for your software version. Enter the PIN on the watch and confirm. You should see a debug settings screen that allows you to enable USB debugging. Also check the don't disable switch to keep the watch usable while it's connected to the charger.
Done!
With ADB enabled, the watch should show up as a device in Android Studio and allow you to install apps as usual. However, there are two things to keep in mind:
First, the custom Xplora launcher will not show your app on the home screen unless your app identifier starts with "com.xplora.", i.e. "com.xplora.yourapp". You can still launch other apps via adb, but for convenience you may consider building a thin wrapper app with a com.xplora identifier that then launches your main app, if porting an existing app where you do not want the change the identifier.
Second, to tell Android that you're building something that runs on a smartwatch, you have to add some lines to your Android manifest:
<manifest ...>
<uses-feature android:name="android.hardware.type.watch" />
<application ...>
<meta-data
android:name="com.google.android.wearable.standalone"
android:value="true" />
</application>
</manifest>
For an example of an app designed to run on the watch, check out the xplay unlocker. You can use the unlocker to maintain debug access across software updates even if the debug pin changes. If all else fails, it also provides a simple reverse shell and a way to sideload and execute java bytecode, ensuring at least some persistence of access to the device.