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The info inflection is a string, "?info", that may be added to an ARK before resolving it in order to request the return of human- and machine-readable metadata describing the identified object and the commitment made to it by its provider. A successful response returns metadata content as HTML intended for human consumption, along with embedded JSON-LD intended for machine consumption. Future extensions are expected that will permit the request and return of alternate formats. Embedded HTML meta tags that repeat some of the metadata using schema.org element names are recommended because not all processors recognize JSON-LD metadata. It is acceptable in the short term also to recognize the older "?" and "??" inflections and to treat them as synonymous with "?info", but their behavior may change in future versions of the ARK specification.
For the sake of discussion, we define some new terms. Resolution of a given ARK (or any URL) may be a multi-stage process starting with the first resolver hostname appearing in the URL form of the ARK when it is submitted for resolution. That Examples are n2t.net and ark.bnf.fr. The first resolver may forward (HTTP redirect) to a second resolver, which may in turn forward to another, and so forth. The content resolver is the HTTP server that normally returns object content directly (ie, without forwarding). The metadata resolver is the HTTP server that, in response to the info inflection, returns metadata content directly. For a given ARK, the metadata resolver may be on a different host from the content resolver. (On the other hand, all three resolvers might also be on the same host.) For example, the N2T.net resolver stores a preservation copy of object metadata and can be configured on a per-ARK basis to respond to the info inflection directly or to forward it.
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