searxng/docs/admin/settings/settings_general.rst

general:

general:
  debug: false
  instance_name:  "SearXNG"
  privacypolicy_url: false
  donation_url: false
  contact_url: false
  enable_metrics: true

debug : $SEARXNG_DEBUG

Allow a more detailed log if you run SearXNG directly. Display detailed error messages in the browser too, so this must be deactivated in production.

donation_url :

Set value to true to use your own donation page written in the searx/info/en/donate.md <searx.infopage> and use false to disable the donation link altogether.

privacypolicy_url:

Link to privacy policy.

contact_url:

Contact mailto: address or WEB form.

enable_metrics:

Enabled by default. Record various anonymous metrics available at /stats, /stats/errors and /preferences.