Check line 495 SAML 2 Metadata Spec: http://docs.oasis-open.org/security/saml/v2.0/saml-metadata-2.0-os.pdf
Check chapter 3 of eduGAIN Profile https://technical.edugain.org/doc/eduGAIN_metadata_profile.pdf
ECCS refers to eduGAIN Connectivity Check. Please visit here: https://technical.edugain.org/eccs/
ECCS Warnings
As part of the GÉANT 2020 Framework Partnership Agreement (FPA), the project receives funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 856726 (GN4-3).