Search for code in GitHub using GraphQL (v4 API)

You can add qualifiers, if you want to search "beef" just in names than change the query like

search(query: "beef in:name", type: REPOSITORY, first: 10) {

for further detail you can look at https://help.github.com/en/articles/searching-for-repositories#search-based-on-the-contents-of-a-repository

Type: CODE is not supported yet. There is no way you can search the code using graphql right now.

Your understanding is right. Just that you are missing one piece. The search you are doing is happening against the type: REPOSITORY. if you replace your search with

search(query: "beef", type: REPOSITORY, first: 10) {

you will get all the repos having beef in their name.