You can change css_class
class "header links" by following
In default theme you can change or if you have specific theme you change there.
/vendor/magento/theme-frontend-luma/Magento_Theme/layout/default.xml
<referenceContainer name="header.panel">
<block class="Magento\Framework\View\Element\Html\Links" name="header.links">
<arguments>
<argument name="css_class" xsi:type="string">header links</argument>
</arguments>
</block>
</referenceContainer>
If you want to add extra links ( Taken from customer module ). you can use below code in you layout
by your block
classes
<referenceBlock name="top.links">
<block class="Magento\Customer\Block\Account\Link" name="my-account-link">
<arguments>
<argument name="label" xsi:type="string" translate="true">My Account</argument>
</arguments>
</block>
<block class="Magento\Customer\Block\Account\RegisterLink" name="register-link">
<arguments>
<argument name="label" xsi:type="string" translate="true">Create an Account</argument>
</arguments>
</block>
<block class="Magento\Customer\Block\Account\AuthorizationLink" name="authorization-link"
template="account/link/authorization.phtml"/>
</referenceBlock>
Need to create block for href=""
/vendor/magento/module-customer/Block/Account/Link.php
public function getHref()
{
return "http://example.com/";
}
You can add html by the referencing <referenceContainer name="header.panel">
I have added code from core modules for reference. recommended to
override by creating new module.
Hope this helps.