Bugfix for favicon .ico format in Magento 2. Necessary for Magento <= 2.1.7. Fixed in 2.1.8.
We don't recognize or support this file extension type
Enable module:
php -f bin/magento module:enable SpringImport_FaviconBugfix
Disable module:
php -f bin/magento module:disable SpringImport_FaviconBugfix
Update system:
php -f bin/magento setup:upgrade