The annotation
parameter takes also the box type, in a similar same way the line annotation works, as a comma-separated list:
- annotation type: box
- xMin
- xMax
- yMin
- yMax
- border_color
- border_width
- fill_color
[gfchartsreports height="400px" type="line" include="3" x_scale_type=linear annotation="box,4.5,8.5,10,25,orange,4,#fd7b1c99;box,1.5,2.5,0,35,black,1,#4042487a"]