As part of the development for the new XML Sitemaps feature in WordPress 5.5, a new esc_xml() function has been added to core that filters a string cleaned and escaped for output in XML. This joins the existing set of functions like esc_html() and esc_js().
While all contents in XML sitemaps are already escaped using this new function, existing code in WordPress core can be updated to leverage it in future releases.
wp_kses_normalize_entities() has been updated accordingly to support this, and now can distinguish between HTML and XML context.
Note: l10n helpers like esc_xml__() and esc_xml_e() are being proposed separately