Mattermost v2.15.0版本的 MD5 值为：b830f1c573090f102e13175fba2d5b44

以下内容为反编译后的 UrlCssBuilder.java 源代码，内容仅作参考

package ch.qos.logback.classic.html;

import ch.qos.logback.core.html.CssBuilder;

public class UrlCssBuilder implements CssBuilder {
    String url = "http://logback.qos.ch/css/classic.css";

    @Override
    public void addCss(StringBuilder sb) {
        sb.append("<link REL=StyleSheet HREF=\"");
        sb.append(this.url);
        sb.append("\" TITLE=\"Basic\" />");
    }

    public String getUrl() {
        return this.url;
    }

    public void setUrl(String str) {
        this.url = str;
    }
}