User story.

As a technical writer I want to be able to group OpenAPI tags under headings for better left-column navigation in API documentation.

Is your feature request related to a problem?

The development architecture that I work with creates different tags for every object type, such as customer, cart, order, etc. That would be manageable if there were only high-level objects like that, but our API is quite large and has many smaller objects that make up those high-level objects, such as customer-type and customer-contact-info. Those two examples would be tagged as customer-type and customer-contact-info. The devs are happy with their tagging style, especially because some of the lower-level objects are used by multiple higher-level objects. That kind of tagging doesn't make for good navigation in the left-column for documentation.

Describe the solution you'd like

Since I can't change the source material, I'd like to improve how it's handled in the documentation. Redoc supports a vendor extension named x-tagGroups that is used to group tags in the side menu. I've used it before and found it to be a very nice, simple enhancement to make navigation easier and documentation more useful. It would be great to see this extension supported in Elements.