How does WordPress connect sites and the wp_users table?

I’m not clear how WordPress connects the wp_users table with the various sites under a Multisite.

Say I have a site with blog_id = x then I would assume there’s a wp_x_users table that contains the ID of the user in wp_users but I don’t see one.

Any suggestions?

On multisite it’s still a single user table for all websites. It identify user relationship with sites on the table wp_usermeta, under the following user meta keys:

• wp_x_capabilities
• wp_x_user_level

There are other meta keys for user options. But I guess there is no difference on other meta fields (like name, display name and etc), so the user will have the same frontend’s meta fields for all sites on the network.