From Shopify Wiki

link_to_vendor(vendor)

This filter creates a link to the label of the vendor with the name that has been given as a parameter. This means essentially:

{{ "Nike" | link_to_vendor }}

would create a link called "Nike" and when people click on it, they will see the label page of the label/vendor "Nike" which is in the most cases a list of all products in the store that are manufactured by Nike.