There is no bid process. Mozilla sets the default search engine to whatever search engine provides the best search results for its users, as far as that can be determined.
This is why the search engine is different in different locales; for example Yandex has way better Russian search results than Google, and hence is the default search engine in the Russian localization of Firefox.
This is why the search engine is different in different locales; for example Yandex has way better Russian search results than Google, and hence is the default search engine in the Russian localization of Firefox.