Context
Context. A campaign lands on /summer-sale while the page lives at /campaigns/2026/summer; a blog whose slug is main-blog should answer at /blog; a legacy path from an old site must keep working. A custom URL is that second address, set on the record, for pages, books, posts, blogs, FAQ pages, questions and custom entity records. It belongs to one site, or to the whole account when its site is left empty.