The email body within Escalation Rule Entries may use the following template tags, which are merged at mail send time:

{!Registration_Type} (Replaced with "Lead" or "Opportunity")
{!Registration_AssignedDate}
{!Registration_ExpirationDate}
{!Registration_Stage}
{!Registration_AssignedPartner}
{!Registration_AssignedContact}

{!Lead_FirstName}
{!Lead_LastName}
{!Lead_Email}
{!Lead_Company}

{!Opportunity_Name}
{!Opportunity_Stage}
{!Opportunity_NextStep}
{!Opportunity_Type}