PROTON_DUMP_DEBUG_COMMANDSx1 2020-06PROTON_FORCE_LARGE_ADDRESS_AWAREx1 2020-06PROTON_LOGx1 2020-06PROTON_NO_D3D10x1 2020-06PROTON_NO_D3D11x1 2020-06PROTON_NO_ESYNCx1 2020-06PROTON_NO_FSYNCx1 2020-06PROTON_OLD_GL_STRINGx1 2020-06PROTON_USE_D9VKx1 2020-06PROTON_USE_SECCOMPx1 2020-06PROTON_USE_WINED3Dx1 2020-06WINE_FULLSCREEN_INTEGER_SCALINGx1 2020-06
Either above the text box within the SET LAUNCH OPTIONS window or within its own window. If in its own Window it can be entirely disabled and invisible when dealing with native titles. As a concept if you'll excuse my image editing skills.
Then that would open a window. Perhaps tooltips when mousing over each option.