Policies on prefix parking

[cthoyt]

A prefix and its corresponding semantic space are substantiated when it's
provable that a semantic space exists by one or more of the following:

1. There's a public place where you can get the entire list of terms.
   Ontologies (e.g., Gene Ontology) and databases
   (e.g., HGNC) usually make this pretty
   straightforwards by offering download links for the ontology or full
   database.
2. There's a working, public URI format string that either lets you get HTML,
   JSON, RDF, or some other kind of information artifact for a given local
   unique identifier. For example, OMIM.PS
   doesn't have a way to get a full list of terms but if you have a given local
   unique identifier, you can use it with the URI format string to retrieve some
   information about the entity corresponding to that LUI.

A potential less strict third criteria for substantiation could be when
references to entities in a semantic space (i.e., in the form of CURIEs) can be
found in public resources or ontologies that are external to the resource in
which the prefix/semantic space are defined. This is more common for historical
prefixes (e.g., OpenCyc references appear quite frequently, but this resource
was taken down more than a decade ago) and is less applicable to new prefix
requests. Therefore, this relaxed criteria will not be considered as sufficient
for substantiation.

We define prefix parking as a special case of a prefix request in which the
corresponding resource/semantic space for the prefix does not yet exist or is
currently under development (and by definition, is not yet substantiated). The
Bioregistry does not explicitly discourage prefix parking, but new prefix
requests qualifying as prefix parking require additional guidelines, partially
motivated by the difficulty of the discussion on
#359.

1. While it's not typically under the purview of the Bioregistry Review Team to
   judge the utility of a prefix nor comment on its corresponding design
   decisions (e.g., choice of local unique identifier scheme, regular expression
   pattern, URI format string), submitters seeking to park a prefix must both
   actively publicly seek out and seriously consider suggestions and advice from
   the Bioregistry Review Team with regards to these matters (e.g., in the issue
   corresponding to a new prefix request). Submissions unable/unwilling to
   follow these guidelines will be dismissed and asked to re-submit after their
   prefix has been substantiated.
2. Submissions to park a prefix must include a primary contact person for the
   resource that is available for public discussion on GitHub. Even though this
   is likely the same as the submitter, it is important that this person can be
   contacted. If they are unresponsive within two weeks of contact regarding the
   parked prefix, then the parked prefix is subject to removal.
3. Parked prefixes that are not substantiated within three months are subject to
   removal. In the case that someone else wants to use that prefix, the fact
   that the parked prefix has not been substantiated will, by definition, result
   in no impact or confusion that would normally result from the removal of a
   prefix.
4. It's not the job of the Bioregistry to support parking prefixes for semantic
   spaces that will not be public or that won't be used in other public
   resources - these can be rejected without further discussion.

Original discussion about prefix parking can be found at
#365.