@Override
	public String getToolTipText(MouseEvent e) {
		int columnIndex = columnAtPoint(e.getPoint());
		if (columnIndex < 0) {
			return null;
		}

		if (isOverHelpIcon) {
			return "Click here for table header help";
		}

		StringBuilder ttBuilder = new StringBuilder();

		TableColumn column = getColumnModel().getColumn(columnIndex);
		TableModel model = gTable.getModel();

		int realIndex = gTable.convertColumnIndexToModel(columnIndex);

		String columnFilterToolTip = getColumnFilterToolTip(model, realIndex);
		VariableColumnTableModel variableModel = VariableColumnTableModel.from(model);
		if (variableModel != null) {
			String description = variableModel.getColumnDescription(realIndex);
			if (description != null) {
				ttBuilder.append(description);
			}
		}

		if (columnFilterToolTip != null) {
			ttBuilder.append("<br><hr width=80%><b>Filters: </b");
			ttBuilder.append(columnFilterToolTip);

		}

		if (ttBuilder.length() != 0) {
			return HTMLUtilities.wrapAsHTML(ttBuilder.toString());
		}

		TableCellRenderer headerRenderer = column.getHeaderRenderer();
		if (headerRenderer == null) {
			return null;
		}
		Component component = headerRenderer.getTableCellRendererComponent(getTable(),
			column.getHeaderValue(), false, false, 0, 0);
		int prefWidth = component.getPreferredSize().width;
		int cellWidth = getHeaderRect(columnIndex).width;
		if (prefWidth > cellWidth) {
			return column.getHeaderValue().toString();
		}

		// handle the case where the user has specifically added a tooltip string
		if (component instanceof JComponent) {
			JComponent jComponent = (JComponent) component;
			return jComponent.getToolTipText();
		}

		return null;
	}
This is the cursor used by BasicTableHeaderUI to tell the user they can resize a column
Ghidra/Framework/Docking/src/main/java/docking/widgets/table/GTableHeader.java