config.tx_replacer {
    enable_regex = 1

    # Only images go to the CDN. The theme's own css/js/fonts are served by the production
    # host: they are already minified by Webpack, gzipped by mod_deflate and content-hashed
    # for a year of immutable browser caching, and keeping them on the page's own origin
    # means they arrive over the connection the browser has already opened rather than
    # costing a second DNS lookup and TLS handshake on the critical path.
    #
    # It also keeps them clear of the pull zone's habit of occasionally wedging a single
    # cache key (10.0s -> 504 errorcode 106 until that key is purged, while the origin
    # serves the same bytes in under 100ms). For an image that degrades one element; for
    # js/main.<hash>.js it would take every visitor's JavaScript down.
    #
    # typo3temp is scoped to generated images on purpose - assets/compressed holds other
    # extensions' concatenated css/js, which belongs on the origin for the same reason.
    # The quote character is captured rather than matched literally, so url() values
    # written with single quotes are rewritten too.
    search {
        10 = /(["'])\/?(fileadmin|uploads|typo3temp\/assets\/(?:_processed_|images))/
    }

    replace {
        10 = $1https://cdn.ep-reisen.de/$2
    }
}