WooCommerce 3 introduced a new format to structured product data called JSON/LD. Despite the fact that this improvement is a huge step forward, some people asked how to remove it.
From our official post release:
Previously, structured data was output inline in our template files (marking up things such as products). In 3.0 we’ve switched to JSON-LD format which keeps our template files tidy and keeps data intact if customisations are made by theme developers.