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+ [ ] For any new components I've made sure that the style can be extended by the consumer using a `className` override.
+ [ ] For any new files I've included the [Apache 2.0 License header](https://github.com/Skyscanner/backpack/blob/master/packages/bpk-tokens/formatters/license-header.js#L2-L16) at the top of the file.
+ [ ] I've updated `changelog.md` for any changes that need to be highlighted in the changelog.
+ [ ] If I've updated `npm-shrinkwrap.json` those changes are intentional.

<!-- Thanks for your PR. Please verify below that you've made all the necessary changes. -->
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+ [ ] For any new web components I've made sure that the style can be extended by the consumer using a `className` override.
+ [ ] For any new native components I've made sure that the style can be extended by the consumer using a `style` override.
+ [ ] For any new files I've included the [Apache 2.0 License header](https://github.com/Skyscanner/backpack/blob/master/packages/bpk-tokens/formatters/license-header.js#L2-L16) at the top of the file.
+ [ ] I've updated `changelog.md` for any changes that need to be highlighted in the changelog.
+ [ ] If I've updated `npm-shrinkwrap.json` those changes are intentional.

Make sure RN styles can be extended in userland
[NOJIRA] Make sure RN styles can be extended in userland
