add_header Content-Disposition inline;

This Nginx configuration directive adds a Content-Disposition header to the response with the value "inline".

The Content-Disposition header is used to suggest a default filename for the content when the user saves it. When the value is "inline", it suggests that the content should be displayed in the browser window instead of being downloaded.

For example, if you have an HTML file that you want to display in the browser instead of being downloaded, you can use this directive to suggest that the file should be displayed inline.

Note that not all browsers support the "inline" value for the Content-Disposition header, so it's possible that the file may still be downloaded instead of displayed inline.