We also use an `__experimental` prefix for any experimental interfaces. This is a signal to those reading our code that it should not be implemented in for production use. Currently this prefix is used in the following ways:
- ⚛️ Product Price new controls ([JS flag](https://github.com/woocommerce/woocommerce-blocks/blob/74badf254ecfe0c7811713a0f847a87f139c69c3/assets/js/atomic/blocks/product-elements/price/supports.ts#L14-L37)).
- ⚛️ Product Title new controls ([JS flag 1](https://github.com/woocommerce/woocommerce-blocks/blob/fd8eeb7f49f0454d746d581bc892cf3c2d9e30cc/assets/js/atomic/blocks/product-elements/title/attributes.ts#L25-L32) | [JS flag 2-1](https://github.com/woocommerce/woocommerce-blocks/blob/df6d820bb47459d56c1329729ab8c364a1b8fddc/assets/js/atomic/blocks/product-elements/title/block.tsx#L84) | [JS flag 2-2](https://github.com/woocommerce/woocommerce-blocks/blob/df6d820bb47459d56c1329729ab8c364a1b8fddc/assets/js/atomic/blocks/product-elements/title/block.tsx#L88) | [JS flag 2-3](https://github.com/woocommerce/woocommerce-blocks/blob/df6d820bb47459d56c1329729ab8c364a1b8fddc/assets/js/atomic/blocks/product-elements/title/block.tsx#L110) | [JS flag 2-4](https://github.com/woocommerce/woocommerce-blocks/blob/df6d820bb47459d56c1329729ab8c364a1b8fddc/assets/js/atomic/blocks/product-elements/title/block.tsx#L114) | [JS flag 3-1](https://github.com/woocommerce/woocommerce-blocks/blob/c734f3e846b8da7d49a03347d92354efd786251f/assets/js/atomic/blocks/product-elements/title/edit.tsx#L45-L52) | [JS flag 3-2](https://github.com/woocommerce/woocommerce-blocks/blob/c734f3e846b8da7d49a03347d92354efd786251f/assets/js/atomic/blocks/product-elements/title/edit.tsx#L98)).
-`npm run build:deploy` uses the feature plugin flag ([env flag](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/c0de18ec0a798c072420c67a689e4cc4d3ac77c9/package.json#L28)).
- webpack creates a `blocks.ini` when running ([env flag](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/961c0c476d4228a218859c658c42f9b6eebfdec4/bin/webpack-configs.js#L110-L119)).
- webpack filters out experimental blocks when building. ([env flag](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/bin/webpack-entries.js#L61-L66)).
- certain E2E tests are skipped if the environment is not met ([env flag 1](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/961c0c476d4228a218859c658c42f9b6eebfdec4/tests/e2e/specs/backend/cart.test.js#L26) | [env flag 2](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/961c0c476d4228a218859c658c42f9b6eebfdec4/tests/e2e/specs/backend/checkout.test.js#L26) | [env flag 3](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/961c0c476d4228a218859c658c42f9b6eebfdec4/tests/e2e/specs/backend/mini-cart.test.js#L18) | [env flag 4](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/961c0c476d4228a218859c658c42f9b6eebfdec4/tests/e2e/specs/backend/single-product.test.js#L8) | [env flag 5](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/961c0c476d4228a218859c658c42f9b6eebfdec4/tests/e2e/specs/frontend/cart.test.js#L29) | [env flag 6](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/961c0c476d4228a218859c658c42f9b6eebfdec4/tests/e2e/specs/frontend/checkout.test.js#L32)).
-`__experimental_woocommerce_blocks_payment_gateway_features_list` hook that allows modification of the features supported by PayPal Standard. ([experimental hook](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/4cedb65367be0d1c4c1f9dd9c016e3b1325cf92e/src/Payments/Integrations/PayPal.php#L86)).
-**Deprecated** - `__experimental_woocommerce_blocks_checkout_update_order_meta` hook when the draft order has been created or updated from the cart and is now ready for extensions to modify the metadata ([experimental hook](https://github.com/woocommerce/woocommerce-gutenberg-products-block/pull/3686/files#diff-af2c90fa556cc086b780c8fad99b68373d87fd6007e6e2ff1b4c68ebe9ccb551R377-R393)). [Deprecated in PR 5017](https://github.com/woocommerce/woocommerce-gutenberg-products-block/pull/5017).
-**Deprecated** - `__experimental_woocommerce_blocks_checkout_update_order_from_request` hook gives extensions the chance to update orders based on the data in the request ([deprecated experimental hook](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/d469a45d572f2c52d7917707c492dfb905ddfac0/src/StoreApi/Routes/Checkout.php#L466-L477)). [Deprecated in PR 5015](https://github.com/woocommerce/woocommerce-gutenberg-products-block/pull/5015).
-**Deprecated** - `__experimental_woocommerce_blocks_checkout_order_processed` hook when order has completed processing and is ready for payment ([deprecated experimental hook](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/accd1bbf402e043b9fc322f118ab614ba7437c92/src/StoreApi/Routes/Checkout.php#L237)). [Deprecated in PR 5014](https://github.com/woocommerce/woocommerce-gutenberg-products-block/pull/5014).
-`__experimental_woocommerce_blocks_add_data_attributes_to_namespace` hook that allows 3PD to add a namespace of blocks to receive block attributes as `data-` attributes ([experimental property](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/4a1ee97eb97011458174e93e44a9b7ad2f10ca36/src/BlockTypesController.php#L88)).
-`__experimental_woocommerce_blocks_add_data_attributes_to_block` hook that allows 3PD to add a block to recieve block attributes as `data-` attributes ([experimental property](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/4a1ee97eb97011458174e93e44a9b7ad2f10ca36/src/BlockTypesController.php#L97)).
-`__experimentalDeRegisterPaymentMethod` function used to deregister a payment method, only used in tests ([experimental function](https://github.com/woocommerce/woocommerce-blocks/blob/f27456dd00fa0b21b29a935943defb18351edf48/assets/js/blocks-registry/payment-methods/registry.ts#L110-L114)).
-`__experimentalDeRegisterExpressPaymentMethod` function used to deregister an express payment method, only used in tests ([experimental function](https://github.com/woocommerce/woocommerce-blocks/blob/f27456dd00fa0b21b29a935943defb18351edf48/assets/js/blocks-registry/payment-methods/registry.ts#L116-L120)).
-`__experimentalOrderMeta` slot that allows extensions to add content to the order meta in the Cart and Checkout blocks ([experimental slot](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/4cedb65367be0d1c4c1f9dd9c016e3b1325cf92e/packages/checkout/order-meta/index.js#L12)).
-`__experimentalOrderShippingPackages` slot that allows extensions to add content to the shipping packages in the Cart and Checkout blocks ([experimental slot](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/4cedb65367be0d1c4c1f9dd9c016e3b1325cf92e/packages/checkout/order-shipping-packages/index.js#L12)).
-`__experimentalDiscountsMeta` slot that allows extensions to add content to the shipping packages in the Cart and Checkout blocks ([experimental slot](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b6a9cc6342696f47cc08686522bdaca7989a6bc7/packages/checkout/discounts-meta/index.js)).
-`__experimental_woocommerce_blocks_hidden` property allows overwriting the `hidden` property for cart item data. This is useful to make some cart item data visible/hidden depending if it needs to be displayed in the Cart Block or the Cart Shortcode ([experimental property](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/9c4288b0ee46960bdc2bf8ef351d05ac23073b0c/src/StoreApi/Schemas/CartItemSchema.php#L439-L441)). This was added in [this PR](https://github.com/woocommerce/woocommerce-blocks/pull/3732) to resolve [this issue with Subscriptions](https://github.com/woocommerce/woocommerce-blocks/issues/3731). This property will not be needed if the blocks replace the shortcode experience, since in that scenario, the `hidden` property would be sufficient.
