Seems like a wah pedal you control with your foot. It acts like a frequency filter, you put it before the guitar amp.

Pretty sure there is also a lot of eq, low cut and such but a wah pedal does do that.

You could automate an EQ sweep but the Wah is a standard tool for guitar players this is why it was my first idea ;)

Just a simple way way pedal would be my guess - 70s technology

You could also do it by breaking up the guitar file into several smaller files/objects and apply EQ sculpting and envelope filter for each section. If you listen to it, you'll hear the EQ changes are very abrupt, on the down beat and not really the smoother sweep of a Wah.