themes-wordpress/blockbase/sass/base/_utility.scss

//Utility classes for Block styles/Patterns:

//Apply to Image block when we don't want margin bottom before caption
.image-no-margin {
	margin: 0;
	& * { //Removes any whitespace created by child elements (a div on the editor, and an image or link on the frontend)
		vertical-align: bottom;
	}
}

//Removes padding on Column block when it has a background color
.has-background-no-padding.wp-block-columns.has-background {
	padding: 0;
}

// For when we do not want the vertical block gap. Needed until we have per-block margin controls.
.mt-0 {
	margin-top: 0 !important;
}