Non-explicit specifiers are ambiguous and require probing for the correct file path on every run, which has a performance overhead.

Note: This lint rule is only active when using --unstable-sloppy-imports.

Invalid:

import { add } from "./math/add";
import { ConsoleLogger } from "./loggers";

Valid:

import { add } from "./math/add.ts";
import { ConsoleLogger } from "./loggers/index.ts";