Why brave search is not open source?

brave search claims to be safer than duckduck go and claims to be the safest but its not open source

Would like to see Brave search become fully open source and allow anyone to self host their own brave search instance just like you can with searx.

Brave search is the only private search engine that gets its search results indipendatly and not rely on a 3rd party like googe or bing.

The reason I like open source is for transparency, to ensure the service your using is not collecting data on you for example requires the code to be open source.