I think this is the motivation behind requiring an npm: prefix. It is a way to virtue signal for devs who buy into the deno goals to push for migrating to non-“legacy” packages. If you see an npm: prefix in a deps.ts file you can consider it tech debt. And potentially set up a lint rule to enforce it in the future. If they had not put an explicit reference in the source (passed through the packages transparently or kept a server side list of packages on npm) then it wouldn’t be colocated with the source and the PR processes. I think this was a good move overall.