MS Graph SharePoint sites search parameter

Greetings,

The search parameter for SharePoint sites in MS Graph yields unexpected results. When I enter the search term "Company" for instance, I get a certain number of sites whose names or displayNames do not contain this term. The https://docs.microsoft.com/en-us/graph/query-parameters#search-parameter specifies the search properties for message collections and users, but not for SharePoint sites.

I'd guess name and displayName are searched properties (seems to be confirmed when I test this), but I'd like to know what additional properties are searched. The properties I get back in the results don't contain the search term, so there must be at least one additional property that is searched.

Example query:

https://graph.microsoft.com/v1.0/sites?search=*Company*

Example result: