Final answer:
Jenny should implement 301 redirects or a custom 404 page for the pages without a new equivalent to maintain user experience and SEO rankings. She should ensure the information on these pages is current, with functional links.
Step-by-step explanation:
If Jenny is in charge of creating the URL mapping file for a website migration and finds pages with no corresponding new page, she should consider implementing 301 redirects to the most relevant existing page or a custom 404 page that assists users in navigation. This process will help maintain a good user experience and potentially preserve search engine rankings by ensuring that any inbound links to those old URLs continue to provide value.
Jenny must check if the information is current by evaluating when the page was last updated and ensuring all links on the page are current and functional. She may also want to consider the role of each page in the overall site structure and whether alternative content could serve the same purpose as the removed or consolidated pages.
By keeping user experience and SEO in mind, Jenny can ensure that the site’s migration minimizes visitor frustration and maintains the website's visibility in search engine results.