If a post has an anchor tag without any href, for example <a></a>, then there is an error in pointRelativeURLsToSourceSESite().

Code with reproduced here for ease of access:

reportBody.find('a').each(function () {
      const $this = $(this);
      let href = $this.attr('href');
      if (!/^(?:[a-z]+:)?\/\//.test(href)) {
        // It's not a fully qualified or protocol-relative link.
        if (href.startsWith('/')) {

href.startsWith('/') throws an error because href is undefined.

Example report with an anchor that is missing an href: https://m.erwaysoftware.com/posts/uid/stackoverflow/78706588

Chat link for the report: https://chat.stackexchange.com/transcript/message/65904497#65904497