Multi-brand storefronts often don’t make it obvious how many distinct vendors they actually carry. The vendor column in the standard export captures it per product - remove duplicates on that column in your spreadsheet and you have the complete list of brands, with a count.

From the CSV, sorting or filtering by vendor gives you a clean breakdown of how many products (and variants) each brand has in the store, which is often the actual question behind "how many vendors does this store carry."

Multi-vendor marketplaces built on Shopify (where vendor often represents the seller, not just a brand) work the same way - the field is populated identically either way.

This is a common first step before reaching out to a store for a wholesale or partnership inquiry, or simply to understand how consolidated - or fragmented - a marketplace-style storefront’s supplier base actually is, without manually clicking through every single product page to compile the list by hand.