thanks for the speedy response. The devtool setting is set to hidden-source-map. I've just skimmed the plugin's source code and it does not set any header. Does that mean that when uploading a sourcemap without a comment reference in the minified file i need to set a HTTP header when uploading?
I've tried reading the CLI's source for some information and it seems that a x-sourcemap header is set. (Unfortunately https://docs.sentry.io/api/releases/post-release-files/ does not provide any information on this). I'll make a pull request for the webpack plugin to include that header if this is the case.
What format should the header value have? E.g. I have a file index.bundle.js and index.bundle.js.map, do i set it to ~/index.bundle.js?