These are filter types! Common in music production/electronic music. And actually very uncannily good representations of them haha

Fastest way I can think to access a lowpass filter with a very clear demo of what it does would be the ableton playground:

https://learningsynths.ableton.com/en/playground

The lowpass basically sets a point above which no frequencies are allowed though (it’s usually a slope and not a hard cutoff, and many variables affect it).