Mark extra files and fields as "Notes" not "Warnings", off by default

[antrim]

The validator returns warnings for unexpected files and fields by default. These warnings might do more harm than good.

• Many, if not most, GTFS data files contain extra files and fields. The adoption path for GTFS extensions usually requires for new files and fields to be published in data before it becomes part of the spec reference.
• Warnings for extra files and fields adds noise to the validation output.
• Warnings might suggest to a naive user that the extra files and fields might represent a problem (this occasionally comes up from consumers of @Trillium-Solutions GTFS datasets).

Suggestions:

• Present extra file/fields as a "Note" rather than a "Warning." I don't think extra files/fields are ever going to be a problem in and of themselves.
• Turn off these "Notes" by default, as they are most often not useful.

[isabelle-dr]

Hi @antrim! I joined the MobilityData team recently :)

With the V2.0.0 of the Canonical GTFS Schedule Validator, we introduced an INFO severity level exactly for this purpose. Two notices can be triggered: UnknownColumnNotice and UnknownFileNotice, as you can see in the documentation. (correct me if I'm wrong @lionel-nj)

Is this solving the issue for you?

[isabelle-dr]

Closing since it has been solved in version 2.0.0