Not only monochrome but also including SVG style/class code so that the icon color ‘flips’ according to color scheme. This means the icon is white with dark color schemes and black with light ones (only tested on KDE Plasma).
Will probably end up including in larger icon themes but wanted to share the standalone icon here for any other uses.
Due to limitations of the forum/image-hosting I have had to place demo PNG files here for view.
All should link to proper SVG files hosted at Gitlab.
The original still has some minor shadow paths included.
The minimal version has these removed and is solely the 3 shapes in varying opacity.
The mono version is thanks to @dirn.
The other reason for posting is to get feedback!
Please let me know if the elements feel ‘right’ - mainly the different opacity levels for the shapes and the size of the icon in comparison to the canvas (ie: how much blank space surrounds the icon when used for something like Application Launcher).