You can set your custom settings in `__INSTALL_DIR__/settings.yml`. That file overwrite the default settings thanks to `use_default_settings: true`
The default settings are available at `__INSTALL_DIR__/searxng-src/searx/settings.yml`. It is recommended to not edit this file directly and to make changes only in the file mentioned above.
Please note that this application is a rolling-release (i.e. each commit is a release) and thus is updated very regularly. People not updating frequently may encounter some bugs or disruptions due to the very nature of this software.