Meta-issue: Provide guidance for proposing extensions and modifications via issue templates

[mfhepp]

Many users of schema.org end up in this repository because they find that the current state of the vocabulary does not fit their individual needs, e.g. missing properties, insufficient specificity, etc.

While feedback from users is essential for schema.org, such proposals often do not end up in actual extensions to the vocabulary, which creates frustration among the submitters and puts a workload on the schema.org core contributors.

It would be good to create guidelines on (1) when and (2) how to propose changes or extensions to the vocabulary.

This could be implemented as one or multiple Github issue templates; for inspiration, see e.g. this collection of issue templates, maybe accompanied by a dedicated page in the documentation.

Here are some first ideas (maybe a bit too specific; we must not discourage users from proposing changes, of course):

Checklist

• My proposal is about the vocabulary, not about problems with existing tools (like validators), the consumption of data by search engines or other applications, or the underlying syntaxes like JSON-LD, Microdata, or RDFa.
• I have read the guidelines on naming and styling in schema.org.
• I understand the basic conceptual model behind schema.org, namely the mechanism for domain and range.
• I am familiar with the data types used in schema.org
• I checked the list of existing types for values etc. (schema:Intangible) and schema:Enumeration insofar they are relevant for my proposal.
• I am familiar with the existing mechanisms for qualitative values via schema:QualitativeValue, quantitative values via schema:QuantitativeValue, and property-value pairs defined outside of schema.org via schema:PropertyValue insofar they are relevant for my proposal.
• I have considered the usage of external standards or numbering schemes for my proposal, e.g. via schema:additionalType or schema:additionalProperty.

Content

• Which applications can be expected to consume the enhanced data? (Very often, proposing an extension included the implicit expectation that major search engines will also actually use it, which will depend on many factors and take time.)
• Can you provide URLs of Web pages that contain the respective information (e.g. that would benefit from the proposed extension)? Ideally, the URLs would be from different sites.
• Did you check if the required information could be modeled with existing schema.org types and properties, e.g. with minor modifications to the text of existing definitions or by adding types to the domain or range?

[mfhepp]

Some aspects are already addressed in the README. Content from there could be reused or moved and replaced by a link.