Use the GET {{apiPath}}/environments/{{envID}}/integrations/{{integrationID}}/versions/{{integrationVersionID}}/asset endpoint to return the SAML assertion for the integration asset specified by integrationID and integrationVersionID.
GET {{apiPath}}/environments/{{envID}}/integrations/{{integrationID}}/versions/{{integrationVersionID}}/asset
integrationID
integrationVersionID