There are many things what can be configured by S3 API but rva-cli will probably never support it directly. Will be nice if we can use this features by some generic settings.
E.g if I want to configure redirect from page.html to http://example.com I can create file page.html.s3metadata with content like:
x-amz-website-redirect-location=http://example.com
Of if I want to define custom routing rules for a bucket I can put XML configuration somewhere else.