This would be a great feature to make Webflow even more SEO friendly!

The last mod tag helps search engines more easily understand when things were updated and can also help best utilize crawl budgets if search engine prioritize only the changes found in the sitemap.

Learn more about this tag in these few articles:
1. https://blogs.bing.com/webmaster/february-2023/The-Importance-of-Setting-the-lastmod-Tag-in-Your-Sitemap

2. https://www.searchenginejournal.com/google-seo-tips-for-news-articles-lastmod-tag-separate-sitemaps/478103/

3. https://www.sitemaps.org/protocol.html

4. https://www.seroundtable.com/google-on-lastmod-tag-in-xml-sitemap-34972.html