nextcloud/core/css/fonts.css

@font-face {
	font-family: 'Open Sans';
	font-style: normal;
	font-weight: 300;
	src: local('Open Sans Light'), local('OpenSans-Light'), url(../fonts/OpenSans-Light.woff) format('woff');
}

@font-face {
	font-family: 'Open Sans';
	font-style: normal;
	font-weight: 600;
	src: local('Open Sans Semibold'), local('OpenSans-Semibold'), url(../fonts/OpenSans-Semibold.woff) format('woff');
}