User would like to know if there is a way to change settings in SNOW system, so attachments would be opening, not downloading after clicking it. Before we're able to view attachments. But now, attachments proceeds to download.

glide.ui.attachment.force_download_all_mime_types is set to true by default in Madrid.

https://docs.servicenow.com/bundle/madrid-platform-administration/page/administer/reference-pages/reference/r_AvailableSystemProperties.html