/usr/share/igtf-policy/classic/CESNET-CA-Root.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.
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#NAMESPACES-VERSION: 1.0
#
# @(#)edca0fc0.namespaces
# CA alias    : CESNET-CA-Root
#    subord_of: 
#    subjectDN: /DC=cz/DC=cesnet-ca/O=CESNET CA/CN=CESNET CA Root
#    hash     : edca0fc0
#
TO Issuer "/DC=cz/DC=cesnet-ca/O=CESNET CA/CN=CESNET CA Root" \
  PERMIT Subject "/DC=cz/DC=cesnet-ca/O=CESNET CA/CN=CESNET CA 3"
TO Issuer "/DC=cz/DC=cesnet-ca/O=CESNET CA/CN=CESNET CA 3" \
  PERMIT Subject "/DC=cz/DC=cesnet-ca/.*"
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