I too would love the dotfiles. Or at least a pointer for the slanted edges. I tried linear-gradient, but I just can't get this right. I use waybar for this, so I might not be able to reproduce this, but I'll try anyway.
It actually shows the volume % notification using a forked version of dunst that only shows the right border.
The screenshot was taken when the volume was being changed.
I like to keep my configurations into separate modules, so they are clearer to read.
In addition, I don't rely on plugins, so many things (such as the prompt) are customized.