Gromit-MPX (GRaphics Over MIscellaneous Things - 
Multi-Pointer-EXtension) is an on-screen annotation tool
that works with any Unix desktop environment under X11
as well as Wayland.
Its main use is for making presentations of some application.

* Desktop-independent
* Hotkey-based
* Configurable
* Fast

The <HOME> and <END> keys are associated by default.
How Use:

HOME:        toggle painting
SHIFT-HOME:  clear screen
CTRL-HOME:   toggle visibility
ALT-HOME:    quit Gromit-MPX
END:         undo last stroke
SHIFT-END:   redo last undone stroke

For change default keys <HOME> and <END> use:
gromit-mpx --key <keysym> --undo-key <keysym>

This remembered over restarts.