Scale and shift is a node in the [graph-editor] that facilitates scaling + shifting signals from an input range to an output range. The equation is: out = in * scale + shift
Unlike things like Eurorack, web synth doesn't normalize its signals to a single range of values (Eurorack uses one volt per octave for a lot of things). Instead, various components/modules output values in ranges applicable to them.
The scale and shift node also supports converting value to/from linear/exponential/logarithmic scales. This is useful for doing things like mapping a linear input value from something like a [lfo-node] or a UI slider into an output range appropriate for controlling a filter cutoff frequency or similar.
To enable this, toggle on the "convert linear/exponential" checkbox in the scale and shift node's [small-view]. That will enable the UI for configuring the mapping.