Class ConditionalFormatRule

// Log the boolean criteria type of the first conditional format rules of a
// sheet.
const rule = SpreadsheetApp.getActiveSheet().getConditionalFormatRules()[0];
const booleanCondition = rule.getBooleanCondition();
if (booleanCondition != null) {
  Logger.log(booleanCondition.getCriteriaType());
}

// Log the gradient minimum color of the first conditional format rule of a
// sheet.
const rule = SpreadsheetApp.getActiveSheet().getConditionalFormatRules()[0];
const gradientCondition = rule.getGradientCondition();
if (gradientCondition != null) {
  // Assume the color has ColorType.RGB.
  Logger.log(gradientCondition.getMinColorObject().asRgbColor().asHexString());
}

// Log each range of the first conditional format rule of a sheet.
const rule = SpreadsheetApp.getActiveSheet().getConditionalFormatRules()[0];
const ranges = rule.getRanges();
for (let i = 0; i < ranges.length; i++) {
  Logger.log(ranges[i].getA1Notation());
}