-**Core flag `WOOCOMMERCE_BLOCKS_PHASE=1`:** anything that is not hidden behind a flag, falls under this category, and it contains all of the code that runs on WooCommerce Core plugin.
-**Feature plugin flag `WOOCOMMERCE_BLOCKS_PHASE=2`**: anything that is behind this flag is code that is shipped to our [feature plugin](https://wordpress.org/plugins/woo-gutenberg-products-block/), the files of blocks behind this flag are also present in WooCommerce Core, just not active.
-**Experimental flag `WOOCOMMERCE_BLOCKS_PHASE=3`**: This flag contains things that we're not shipping yet, so unfinished work mostly. These features are only available in developer builds of the plugin.
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 tag list ([JS flag](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/tag-list/index.js#L29-L33)).
- Draft order and cleanup process ([PHP flag](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/e167b2c99c68e8113b4e371fefdd6f9a356ed2e8/src/Domain/Services/DraftOrders.php#L42-L51)).
- Payment API ([PHP flag 1](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/07387889ec3a03769eb490821ee608d4e741e942/src/Domain/Bootstrap.php#L92-L94) | [PHP flag 2](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/07387889ec3a03769eb490821ee608d4e741e942/src/Domain/Bootstrap.php#L245-L254)).
- ⚛️ Product Price new controls ([JS flag 1](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/price/attributes.js#L13-L44) | [JS flag 2-1](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/8d2f0ad8ade2c7217769b431f93de76d6cfacf6e/assets/js/atomic/blocks/product-elements/price/block.js#L116) | [JS flag 2-2](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/8d2f0ad8ade2c7217769b431f93de76d6cfacf6e/assets/js/atomic/blocks/product-elements/price/block.js#L114) | [JS flag 2-3](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/8d2f0ad8ade2c7217769b431f93de76d6cfacf6e/assets/js/atomic/blocks/product-elements/price/block.js#L91) | [JS flag 2-4](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/8d2f0ad8ade2c7217769b431f93de76d6cfacf6e/assets/js/atomic/blocks/product-elements/price/block.js#L95) | [JS flag 2-5](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/8d2f0ad8ade2c7217769b431f93de76d6cfacf6e/assets/js/atomic/blocks/product-elements/price/block.js#L106) | [JS flag 3-1](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/price/edit.js#L59-L108) | [JS flag 3-2](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/price/edit.js#L114-L131)).
- ⚛️ Product Title new controls ([JS flag 1](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/title/attributes.js#L21-L40) | [JS flag 2-1](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/title/block.js#L70-L72) | [JS flag 2-2](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/title/block.js#L94-L95) | [JS flag 2-3](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/title/block.js#L104) | [JS flag 3-1](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/title/edit.js#L47-L54) | [JS flag 3-2](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/title/edit.js#L77-L107) | [JS flag 3-3](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/title/edit.js#L116-L129)).
- Utility function to pass styles to a block ([JS flag](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/9ebddbc5d21eb3cc67fedddbccbd86453313eb64/assets/js/atomic/utils/block-styling.js#L6-L12)).
- Feature to create an account from the Checkout block ([PHP flag](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/4cedb65367be0d1c4c1f9dd9c016e3b1325cf92e/src/Domain/Services/CreateAccount.php#L40)).
- Inserting Product Element blocks globally from the inserter ([JS flag](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b3a9753d8b7dae18b36025d09fbff835b8365de0/assets/js/atomic/blocks/product-elements/shared/config.js#L25-L27)).
-`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)).
-`__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** - `__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-gutenberg-products-block/blob/b07883b8b76feeb439d655b255507b24fc59e091/assets/js/blocks-registry/payment-methods/registry.ts#L114)).
-`__experimentalDeRegisterExpressPaymentMethod` function used to deregister an express payment method, only used in tests ([experimental function](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/b07883b8b76feeb439d655b255507b24fc59e091/assets/js/blocks-registry/payment-methods/registry.ts#L120)).
-`__experimentalRegisterCheckoutFilters` and `__experimentalApplyCheckoutFilter` methods included with `@woocommerce/blocks-checkout` package. They allow registering and applying a filter to certain parts of the Cart and Checkout blocks ([experimental method 1](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/3e59ec9842464f783f6e087947e717fa0b0a7b1b/packages/checkout/registry/index.js#L2) | [experimental method 2](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/3e59ec9842464f783f6e087947e717fa0b0a7b1b/packages/checkout/registry/index.js#L17)).
-`__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 in a Cart item data array that allows overwriting the `hidden` property. This is useful to make some cart item data visible/hidden depending if it needs to be displayed in Blocks or shortcode ([experimental property](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/9c4288b0ee46960bdc2bf8ef351d05ac23073b0c/src/StoreApi/Schemas/CartItemSchema.php#L439-L441)).
