CodeEditor use ACE editor under the hook.

With Hacker’s Keyboard on Android, we can use some of ACE’s keyboard shortcuts:

Tip: Press Ctrl +, we can see ACE settings. And choose keybinding as ACE.

Some of my favourite shortcuts with Android Hacker’s Keyboard

Ctrl + D = delete  
Ctrl + Shift + D = duplicate  
Ctrl + H = Replace  
Ctrl + [ (or ])= indent
Ctrl-P = Go to matching bracket  
Ctrl-Alt-Up = Add multi-cursor above  
Alt + 0 = Fold all  
Alt + Shift + 0  
Alt + L  
Alt + Shift + L

See all key shortcuts here:

https://github.com/ajaxorg/ace/wiki/Default-Keyboard-Shortcuts

Also https://ace.c9.io/demo/keyboard_shortcuts.html