I considered 'restricted HTML' as unnecessary and set it ‘disable’. Because I thought it possible to re-enable. However, I have not found a disabled format on UI.
Since there is no choice, I decided to newly register. The same registration as the default machine name 'restricted_html' conflicts. Imagine the data is left somewhere. I could not find it even if I looked for a database. Is it possible to restore by setting file or something?
I am using Drupal 8.4.2.