What is User Information List?

List with stores information of user with columns such as User Picture, Email, Display Name, Login Name etc

This is a Standard SharePoint List. but this list is a Hidden list. The user information list is found in this url https://Sitename/_catalogs/users/simple.aspx. This list is a secured list . if you have administrator/ siteowners permission users only can view the list.

Another info to add on top of this - Any user added to the site, be it a people & group or a people picker, the user is added to this list. The IDs for the users are generated based on the order in which the users are added. Hence each site would have its own user information list & the IDs would change from site to site.

The User Information List (“/_catalogs/users/simple.aspx” or “_catalogs/users/detail.aspx”) is a hidden list in each site collection that is only visible and accessible to Site Collection Administrators. The User Information List stores metadata information about a user. Some metadata examples are Display Name (name), Login Name (samAccountName), Department, Picture, Email, SID (determines authorization rights), etc.

SharePoint User Information List stores information about a user by having some metadata set up for the user. Some examples are User Picture, Email, DisplayName, LoginName etc.