MediaWiki

Using Cloudflare R2

//The url used for the API (PutObject, etc.)
$wgFileBackends['s3']['endpoint'] = 'https://my-custom-url';
//The url used for showing images. $1 is translated to the bucket name.
$wgAWSBucketDomain = '$1.my-custom-url';

source: https://github.com/edwardspec/mediawiki-aws-s3/blob/master/README.md