The "/rchvdwnld" page:

Short for "archive download". This page should have a single name= query parameter that is a check-in hash. It present a menu of possible download options for that check-in, including tarball, ZIP, or SQLAR.

This is a utility page. The /dir and /tree pages sometimes have a "Download" option in their submenu which redirects here. Those pages used to have separate "Tarball" and "ZIP" submenu entries, but as submenu entries appear in alphabetical order, that caused the two submenu entries to be separated from one another, which is distracting.