/usr/share/igtf-policy/classic/TERENA-eScience-SSL-CA-3.namespaces is in igtf-policy-classic 1.88-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12  | ##############################################################################
#NAMESPACES-VERSION: 1.0
#
# @(#)1db3b27f.namespaces
# CA alias    : TERENA-eScience-SSL-CA-3
#    subord_of: DigiCertAssuredIDRootCA-Root
#    subjectDN: /C=NL/ST=Noord-Holland/L=Amsterdam/O=TERENA/CN=TERENA eScience SSL CA 3
#    hash     : 1db3b27f
#    (generated automatically from 1db3b27f.signing_policy)
#
TO Issuer "/C=NL/ST=Noord-Holland/L=Amsterdam/O=TERENA/CN=TERENA eScience SSL CA 3" \
  PERMIT Subject "/DC=org/DC=terena/DC=tcs/.*"
 |