You can find this information in the Eikon database, though the database itself requires you to access a specific terminal in the Research Commons, or make a reservation for use of a virtual machine for this purpose. That said, the database includes information on takeover defenses in company profiles. Go to the ESG tab, and it's under 'Corporate Governance' - 'Takeover Defense'. The resulting page will give you information on board structure, voting provisions, and provisions in force.
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