function parseSourceMap(content) {
    if (content.startsWith(')]}')) {
        content = content.substring(content.indexOf('\n'));
    }
    if (content.charCodeAt(0) === 0xFEFF) {
        // Strip BOM at the beginning before parsing the JSON.
        content = content.slice(1);
    }
    return JSON.parse(content);
}
Parses the {@link content} as JSON, ignoring BOM markers in the beginning, and
also handling the CORB bypass prefix correctly.

@param content the string representation of a sourcemap.
@returns the {@link SourceMapV3} representation of the {@link content}.