This canonical request has been extracted via boto3 source code modification.
HEAD /my-bucket/folder/example-object.txt host:minio.mydomain.com x-amz-content-sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 x-amz-date:20230608T220550Z host;x-amz-content-sha256;x-amz-date e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
The corresponding string-to-sign is
AWS4-HMAC-SHA256 20230608T220550Z 20230608/us-east-1/s3/aws4_request e2d4be537009ba634ecc7a2717df2d74e612c63d31cf4bd8cb94eaf43be3665b
Note that the checksum of the string-to-sign does not match since some details of the canonical request have been modified.