Yes, and yes
#are presets made up entirely of modules?
lyric solar
https://github.com/mastercomfig/mastercomfig/tree/release/config/cfg/presets
The commands in these files can be overridden in your autoexec
quick laurelBOT
lyric solar
Also, low and very-low disable dsp, and very-low also disables decals.
But these are baked into the vpk
lyric solar
Yep, in fact all those files are in each of the preset vpks. It's just when you download say medium, it has the line preset=medium baked in and runs the medium.cfg