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Magento 2 Product Visibility Grid
Did you every wonder why your product is not showing up in a category in Magento?
Magento has a complex way of building a product collection. Due to several conditions, indexes, plugins and other complexities determining whether a product should show is not that straightforward."
Details and Tools/Modules:
https://github.com/Itonomy/magento2-product-visibillitygrid