Select the Color Ramp node before generation.

The checkboxes indicate which mode and which interpolations are included in the generation.
By default, all are activated for maximizing randomness.

Min Stops - Minimum number of stops.

Max Stops - Maximum number of stops.

Available range from 1 to 20.

The parameters Clamp Min and Clamp Max are used to activate and deactivate the channel.

Clamp Min - The probability of how often this channel will be 0(disabled). The HIGHER the value, the more frequent.
Clamp Max - The probability of how often this channel will be equal to 1(max value). The LOWER the value, the more frequent.

Example:

Red Channel

Clamp Min = 1

Clamp Max = 0.46

The channel value is clamped and always  0.

Green Channel

Clamp Min = 0

Clamp Max = 0

The channel value is clamped and always 1.

Blue Channel

Clamp min = 0.15

Clamp Max = 0.85

Min Blue = 0.1

Max Blue = 0.25

The channel value will be generated in the range (Min Blue, Max Blue). Periodically it will be equal to 0 or 1.

By setting lower values for channel ranges(Min Red Max Red, Min Green Max Green, Min Blue Max Blue), the color will be darker and vice versa.