I found this while roaming around.
https://rail-sim.de/forum/filebase/entry/397-minimal-fahrpult-hud-minimalist-hud-v-1-2/
The instructions are in German and English.
I Made a copy of the frontend folder and labeled it as original HUD and put the new files in the frontend folder I copied from. This way it is easier to go back to the original HUD by just renaming the files.
The opacity can be changed in the usual manner by accessing the options menu through the pause button on the HUD.
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