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Last tested: Mar 3, 2020
If you see "Cross-Origin Read Blocking" error for self-created custom visualizations, and the host url is https://raw.githubusercontent.com/....
This is due to the fact that https://rawgit.com/ is no longer in service. You should migrate the js file into other services such as S3 bucket, GCS or https://raw.githack.com/ etc.
This content is subject to limited support.