../nix/<storepath> should return a HTTP error. Otherwise, mirror-channel.pl will happily mirror the error page.
BDY5KCG7Z65C24KALK5QIGR6LRTDY6EW36VBTTYT75SMG6ODIJZAC
AKAZKCR6GFCZQBR2ZJSZEI3SXW4S25V7X7JGHUYNUITQQSAVAF5AC
FPK5LF53CFUEKFYJ3IYXT4UTVC6IITWJOCFATMC4PLHEUP5SIEAAC
5NO7NCKTMM5ZW7JYOETUFOSWK2ACTXWDZGJAFXZN6L3OF6BFTNOQC
ZRBXLKFOKTP3S3OABM2BRPAHS2RFLYZSEFCLGCAQ47WSFMWWPGJQC
error($c, "Unknown channel `$channelName'.");
notFound($c, "Unknown channel `$channelName'.");
error($c, "Path " . $path . " is no longer available.") unless isValidPath($path);
if (!isValidPath($path)) { $c->response->status(410); "Gone" error($c, "Path " . $path . " is no longer available."); }
if (!isValidPath($path)) {
$c->response->status(410); "Gone"
error($c, "Path " . $path . " is no longer available.");
}