crt
What is a .crt file?
application/x-x509-ca-cert
A .crt file holds an X.509 certificate, most often PEM-encoded (Base64 text) though sometimes DER binary. The extension is a convention for the public certificate half of a TLS identity, as opposed to the private .key file. It carries the subject, issuer, validity window, public key, and signature.
How to use a .crt file
Use an example .crt to test certificate parsers, trust-store importers, and TLS tooling, or as input for .crt-to-.pem/.der conversion. Sample material only, self-signed and clearly labelled.