This directory /usr/share/pki/ca-trust-source/ contains CA certificates and
trust settings in the PEM file format. The trust settings found here will be
interpreted with a low priority - lower than the ones found in
/etc/pki/ca-trust/source/ .
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QUICK HELP: To add a certificate in the simple PEM or DER file formats to the
list of CAs trusted on the system:
Copy it to the
/usr/share/pki/ca-trust-source/anchors/
subdirectory, and run the
update-ca-trust
command.
If your certificate is in the extended BEGIN TRUSTED file format,
then place it into the main source/ directory instead.
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Please refer to the update-ca-trust(8) manual page for additional information.