NEW-PROTOCOL: document what needs to be done to add one #6263
One thing missing is a discusson on the significance of a protocol. Just because it can be shoehorned into a URL syntax doesn't mean it should be included in curl, if it's only used by a total of 3 people in the world, for example. This document would also be a good place to mention that adding a protocol involves additional work for curl maintainers from that point forward into (potentially) infinity, a demand that should not be taken lightly. If we can come up with hard figures on the potential number of users of a protocol, we should add those. e.g. Are there even 100 people in the world still using dict? Are there 500 still using gopher? Those two are at the low end of what might be acceptable (they might below the bar if it were up to me). Or, maybe figures on the minimum number of independent servers in the world running a protocol would be easier to quantify.
I hear you, but that's a tough one to put into words. How about adding a small section like this?
Wide and public use
The protocol shall already be used or have an expectation of getting used widely. Experimental protocols are better off worked on in experiments first, to prove themselves before they are adopted by curl.