Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Cell/Cell.php
public function isMergeRangeValueCell()
    {
        if ($mergeRange = $this->getMergeRange()) {
            $mergeRange = Coordinate::splitRange($mergeRange);
            list($startCell) = $mergeRange[0];
            if ($this->getCoordinate() === $startCell) {
                return true;
            }
        }

        return false;
    }
public function isMergeRangeValueCell()
    {
        if ($mergeRange = $this->getMergeRange()) {
            $mergeRange = Coordinate::splitRange($mergeRange);
            list($startCell) = $mergeRange[0];
            if ($this->getCoordinate() === $startCell) {
                return true;
            }
        }

        return false;
    }
Is this cell the master (top left cell) in a merge range (that holds the actual data value).

@return bool