Hi @eclev91,
Thanks for taking the time to explain what you are trying to achieve here. I can see you are customizing the packing slip output using the wcshipping_packing_list_html filter and have noticed that only the HTML and order ID are available, while other shipment related data used internally by the plugin is not easily accessible.
At the moment, the wcshipping_packing_list_html filter is intentionally limited to modifying the generated HTML output. The internal shipment and label data you referenced are handled within the plugin’s internal classes during generation, and they are not currently exposed through that filter or a public API. Because of this, accessing those objects directly, such as the Loader instance or the related classes it initializes, is not something that is supported externally.
If you need additional shipment or label information, you may still be able to retrieve some related data using the order ID via standard WooCommerce order methods, for example using wc_get_order() and inspecting the order items and metadata. That said, the full shipment objects used internally by WooCommerce Shipping are not currently exposed in a way that can be accessed from custom code outside the plugin.
Your suggestion about registering the Loader class as a singleton or exposing more structured data for packing slip customization is a thoughtful one. Since this would involve a change to how the plugin exposes its internal data, the best path would be to submit it as a feature request so the development team can review it.
You can share that request here: https://woocommerce.com/feature-requests/shipping/. If you need further support, feel free to let us know.
Thanks for reaching out and for your patience while we looked into this! I really appreciate you taking the time to report this — it genuinely helps us improve.
I’ll go ahead and mark this thread as resolved for now. If anything changes on your end or you need further assistance down the road, feel free to start a new thread anytime — we’re always happy to help!