Add MIME-types to Nextcloud

Valid for Nextcloud 11 – 16.

Create new file

vi /var/www/nextcloud/config/mimetypemapping.json
{
"eml": ["message/rfc822"],
"dcm": ["application/dicom"],
}

Update tables

php occ maintenance:mimetype:update-db --repair-filecache
php occ maintenance:mimetype:update-j

Open file

See also

/var/www/nextcloud/resources/config/mimetypemapping.dist.json