.crt

X.509 certificate file, read by TLS libraries and browsers

Syntax highlighted

Format facts

MIME type: application/x-x509-ca-cert
Apple UTI: public.x509-certificate
Stock Quick Look: shown as plain text
Planned approach (census): syntax-highlight
Icon hint: generic-icon
Prevalence: universal

Renderer note (from the census)

pure Go parse PEM blocks

Gotchas: PEM or DER