With format auto-detection enabled, a client whose User-Agent matched the
Clash or JSON regex was routed straight to that format handler. For a
subscription whose entries convert to neither format (an MTProto-only
subscription, for example) the handler returns an empty document and the
request ended as 404, breaking a URL that served the raw list before the
toggle. The auto-detect branches now serve the detected format only when
it produces content and otherwise continue to the raw response; the
explicit format endpoints keep answering 404 for empty documents.
MHSanaei
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