It offers a JavaScript coding front end which calls a framework of objects using a mainly Java back end to control Android.
Coding can be done directly in the DroidScript app on a phone or tablet or from a Browser on a PC etc. connected to the device by WiFi to provider a richer coding environment.
If you install DroidScript, you will have access to the best docs but a version of those docs can be seen at https://alex-symbroson.github.io/Docs/
DroidScript allows you to control many aspects of your phone, tablet or Chromebook for free but some more advanced features require plugins or a Premium subscription.
Some plugins are totally free. Others are free if you have a premium subscription.
The menu in DroidScript will show you the prices of plugins and subscriptions. They vary from country to country.
There is also a wiki at https://wiki.droidscript.me.uk/ which used to be the best source of information but the built-in docs have now far outstripped it.
When I looked for that today, I found it in my drafts folder.
It appears I saved it while I fetched the Google Play URL to download DroidScript and was somehow distracted.
The url is https://play.google.com/store/apps/details?id=com.smartphoneremote.androidscriptfree