And well-earned, too. MinIO is a really neat solution for keeping local data available via the same protocol as that in the remote S3 buckets. I do wish there was something below it, though, complexity-wise, just a little application that serves a directory as an S3-compatible bucket. MinIO can feel a little much for simple testing scenarios and the like.
Another alternative:
https://github.com/gaul/s3proxy
(supports serving ("proxying") from file system)