There is a function for parsing jsonc in std, but these files are sometimes used just to store constants. In these cases it's more natural to import them, otherwise the happy path is to have the comments in the code and import a regular json, but with lost maintainability as it's often better to have comments sit with the data. I ended up importing a json.
maybe allow
import file from "file.jsonc" assert { type: "jsonc" }